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Concourse 2

Time, tense and aspect: overview and index

hour glass

If you feel comfortable with the following concepts ...

... then feel free to use this index to go to the area that interests you.

Talking about the Present Talking about the Past Talking about the Future Talking about Always
There is also a guide to:
Teaching tense and aspect      

Otherwise, read on ...


deck clearing

Clearing some conceptual decks

Before we can look at tense forms, meaning and use in English, we have to get four things clear:

Time:
clock
This is a non-linguistic concept of when an action or a state is set.  It is non-linguistic because the relationship between time and grammatical form is often unclear with past forms used to speak about the future, future forms appearing in the past and so on.
Traditionally, we have three choices:
  • Now: the action / state is set in the present, e.g.:
        I am on the train
        Please come with me
        If you could come with me, it might help
  • Past: the action / state is set before the present, e.g.:
        She arrived late
        I was to have attended the meeting but couldn't be there
        Where would he have gone next?
  • Future: the action / state is set after the present, e.g.:
        My train leaves soon
        Do you think she will be at the party?
        I will have been here for years by then
  • but we can add a fourth and that concerns Always: the action / state is set in the past, the present and the future, e.g.:
        I like apples
        She is working too hard these days
        We tend to go to bed quite late
    This expression of time in a language is often called timeless because it is not, obviously tied to a specific time.
    Habitual expressions fall into this category along with expressions of liking and disliking which are assumed to apply to the past, present and future.
Tense:
tents
No, not that sort.
This is the name we give to the form the verb takes.  It refers to the form of the verb and the grammatical function of any primary auxiliary verbs involved.  In English it is often averred that there are just two:
  • past tense: e.g., made rather than make
  • present tense: e.g., comes rather than came
  • but we'll add a third because English most certainly does exhibit future forms (such as will go rather than goes) even if it has no 'proper' future tense signalled by an alteration in the form of the main verb as many languages do (and many don't)
Aspect:
grimace
This refers to how the user of the language views the event or how the event is experienced.  There are many of these and they are signalled in languages in a bewildering number of ways.  For the purposes of analysing English verb form, meaning and use, we'll focus on:
  • perfect: relating two times (past to pre-past, present to pre-present, future to post-future).  An alternative way to see this (explained below) is that perfect aspects set times within other times.
  • progressive: ongoing
  • continuous: current
  • habitual: routine
  • iterative: repeated
  • durative: long lasting
  • prospective: looking forward
Modality:
construct
The expression of tenses is often allied to modality because, by definition, the future is uncertain, we may speculate about the past and we may not be sure of our facts even in the present.  In all tenses, we can speak of our concerns with regard to willingness, ability, uncertainty, likelihood or duty.
Modality concerns the view that the speaker / writer wishes to convey regarding four key concepts:
  • the truth or otherwise of a proposition: relating to how the user of the languages perceives the likelihood of something being the case.  For example, expressing doubt or certainty.
    This is known as epistemic modality, from the Greek for knowledge.  E.g.:
        That might have been her father
        She'll probably be late
        I expect he's upstairs
    etc.
  • obligation: relating to the language user's understanding of whether an obligation or its lack is intended to be expressed.  The obligation can vary in strength and be legal, ethical, moral or advisory.
    For example, there is an external obligation, an internal sense of duty, a lack of obligation or an expression of advice.
    This is known as deontic modality from the Greek for being a needed duty.  E.g.:
        They shouldn't have told you that
        It would be better if you didn't
        You ought to stay
  • ability and willingness: this expresses the language user's view concerning how possible it is for someone or something to do what the verb suggests or how willing they are to do it.
    Because of the sense of power and willingness, this is called dynamic modality from the Greek for power.  E.g.:
        I couldn't safely have driven any faster
        I won't be able to come
        I will get it done for you
        I can't help, I'm afraid
  • necessity: concerns the language user's view of a sense of inevitability so any statement which implies an unavoidable logical conclusion falls into this category.  Essential truths about the workings of the natural world or concepts of definitions of states fall into this category.
    It is called alethic modality from the Greek for truth.
        If it was the colour you described, it must have been a buzzard
        Even on Pluto, Newton's laws will apply
        Two and two must make four

Here's the cut-out-and-keep guide to summarise this.

summary

Modality is not included in what follows because that is covered elsewhere in the section dedicated to modality which you can go to here.


clarity

Some examples to make this clear


Example Time Tense Aspect
That'll be the postman Now Future simple Continuous
he is here now signalled by ''ll' + bare infinitive he is standing outside the door
I have always arrived on Sunday Always Present perfect Habitual
signalled by the adverb signalled by the form of the verb and the auxiliary this is a routine
He thinks so Now / Always Present simple Continuous
this is, was and will be his state of mind signalled by the -s inflexion this is a current state
John is writing a book Now Present Progressive
this is one of his current occupations signalled by is + -ing this is an ongoing action
John is always banging on about it Always Present Iterative
signalled by the adverb signalled by is + -ing a repeated action
Murray hits a backhand down the line Now Present Progressive
commentary on current actions signalled by -s describing an action in progress
I have finished Present Present perfect Perfect
describing a current situation signalled by the form of the verb and the auxiliary the present with an embedded past idea
I leave tomorrow Future Present Simple
signalled by the adverb signalled by base form of the verb with a Ø inflexion a one-off event
I was staying at the Ritz then Past Past Durative
signalled by the adverb signalled by the auxiliary + -ing the state went on for some time
He's going to fall Future Present Prospective
signalled by the context signalled by the verb forms current opinion of an event after now
What will you do if she doesn't arrive? Future Present Simple
signalled by the if-structure signalled by -s a one-off event
What would you do if she didn't arrive? Future Past Simple
signalled by the if-structure signalled by didn't + bare infinitive a one-off event

We can see from even this short list, that time, tense and aspect do not exist in a one-to-one relationship.  Tenses are not, formally, tied to time and aspect is not always signalled by formal changes in the verb.


start

The starting point

Before we can consider how English encodes notions of time, we have to decide what sort of tense system it actually has.
This may not be a question many practising teachers ask but it is important.
This site works from the premise that English has a very simple tense inflexion system but a complex aspectual tense system.
What do we mean by this?
Well, if, for example, we take the past tense of a verb in English such as walk, we find that the only change we have to make to the base form of the verb is to add -ed to the verb and that gives us walked, of course.  If we form what we are pleased to call a simple future in English, we simply add an auxiliary verb and arrive at will walk.  Those are the only changes we make to simple aspects.
Even when we make a progressive form, we can see from what follows that very small changes are required.
That means that the language is defective when we compare it with two other reasonably closely related languages such as French and German.  Here's how it looks:

Person Past verb forms Future verb forms
Language English French German English French German
First singular walked
was/were walking
marchais ging will walk
will be walking
marcherai werde gehen
Second singular familiar gingst marcheras wirst gehen
Second singular distanced marchiez gingen marcherez werden gehen
Third singular marchait ging marchera wird gehen
First plural marchions gingen marcherons werden gehen
Second plural familiar marchiez gingt marcherez werdet gehen
Second plural distanced gingen werden gehen
Third plural marchaient marcheront

You can see that in the past in French, there are five possible forms to choose from and in German, there are four.  For the future, for which French can inflect the verb itself, we have a choice of six forms and in German, which also uses an auxiliary verb for the tense, the verb of choice gives us five forms to choose from.
Our choice depends on whether we are talking about first, second or third person forms, whether we are being polite and distanced or familiar and friendly or whether we are referring to plural or singular subjects.
English does none of that and is wholly defective in this respect, relying on a single form for all persons, all social relationships and all numbers.
To complicate matters further, French also has an aspect system and the verb forms above are just one of the possible selections because French also used the verb have to form a tense superficially similar to the English present perfect but which does not signal the same kind of relationship to time at all.  The forms constructed with the
The past tense forms in French set out above qualify for translation into English as imperfective forms, akin to I was walking rather than I walked.  The same form is used, incidentally, when English would employ the used to formulation for past habits.  When French forms the tense with an auxiliary verb such as in:
    J'ai marché
the translation would be I walked, not I have walked.
German, too, can form a tense in a similar way but that form, too, does not carry the same aspectual considerations as the English form does.  It is quite arguable, in fact, that German does not have an aspectual tense system at all.  The German tense formed with an auxiliary such as in:
    Ich bin gegangen
can be translated either as I walked or I have walked.
Equally, as we see above, Standard German makes no distinction between imperfective progressive events and perfective simple ones.
To some extent, too, both French and German are defective because neither language distinguishes the verb forms for all numbers, persons and social relationships.  English, however, is almost wholly defective.

The examples above are of other European Indo-European languages which are closely related (comparatively) to English.  Other inflecting languages, such as the Slavic languages, other Romance languages like Spanish and Portuguese and Greek exhibit the same kinds of inflexions for person, social distance and number.
When we venture beyond this language grouping, things become even more complex and distinct.
If you find yourself teaching an inflecting language, considerable classroom time needs to be devoted to teaching and correcting the inflected forms of tenses.

The moral in all this is that proceeding in English to focus on form rather than meaning is not a sensible way to go.  The tense forms themselves can be taught in minutes, even when we form aspects with the very irregular verb be.
The focus in teaching English has to be placed on meaning and for that to succeed, aspect is the key.

To do that, of course, requires you to become something of an expert on aspect in general and to be able to identify what the aspects in English do in terms of communication of notions and perspectives.  For that to happen, some common confusions need dispelling.


progressive and continuous

The confusion between progressive and continuous

I think they're talking nonsense  

It is unhelpful to assume that continuous and progressive are simply alternative words for the same aspect.  We may, somewhat loosely, call the tense form something like present / past / perfect etc. continuous but when we consider aspect, we need to be a little more careful.
Nevertheless, it is true that in English little distinction in verb forms is made between continuous and progressive aspects so, for example:
    John is working at his desk now
is progressive insofar as it refers to an action in progress, and
    I am staying at The Ritz
is continuous insofar as it refers to a background state rather than an action currently in progress (I may be nowhere near The Ritz at the time of speaking).
As we shall shortly see, both these aspects can be realised through apparently simple forms of the verb, although the construction with the primary auxiliary be and the present participle is the most common choice.
It is important that teachers of English are aware that other people's languages may reserve explicit verb forms to distinguish between progressive and continuous aspects.  Other languages, such as German, make no distinctions at all.

Continuous aspect
fairy
describes a current state of affairs such as, e.g.:
    I believe in fairies
    He loves me
    He is loving the attention
    He hated me
    We are on holiday
    She is living in a guest house
etc.
The clue is in the name – the aspect refers to the speaker's perception that something is a continuing state of affairs rather than a progressive or repeated action.
The continuous aspect does not always require the auxiliary + -ing.  It can be inherent in both the simple form and the auxiliary + -ing forms of the verb.  This is especially true, of course, with verbs such as think, believe, hate, understand, like etc. which contain the sense of the continuous semantically so do not exhibit any grammatical signalling of the continuous state.
Some of the examples above are simple tense forms but they nevertheless refer to a continuous state.
Progressive aspect
typing
describes an ongoing action such as
    I'm typing this sentence
    He runs the length of the field and scores
    She is taking liberties
    We were eating in my favourite restaurant
etc.
The clue is in the name – the aspect refers to the speaker's perception that something is, was or will be in progress, i.e., an ongoing action.
Notice, again, that the progressive aspect does not always require the auxiliary + -ing.  It can be inherent in both the simple form and the auxiliary + -ing forms of the verb.  For example
    Look, I now turn over the paper and there is the shape
    Here she comes!
    I acknowledge receipt of your letter

The -ing form of the verb can lead to some ambiguity because it can signal both continuous and progressive aspects of the verb.  That is to say, it can signal a background event which is perceived as taking place in the present but is not necessarily something being done right this minute or a progressive, ongoing action happening now.
Compare, for example:
    She is studying French at university
which could imply that right this minute she is in a classroom or the library actively studying but probably refers to a continuous background event.  She may not, at the time of speaking, be anywhere near the university in question, with
    She's in the garden, pulling up weeds
which, because of the nature of the act and the prepositional phrase, almost certainly does refer to the present moment and is progressive rather than continuous.
The same form can also signal repeated events when it is used with a verb which cannot be conceived as progressive or continuous such as knock in:
    Someone is knocking at the door
which is not progressive or continuous but iterative in meaning.  See below under telicity for more on this.


stative

The confusion between stative and dynamic

I'm thinking about it  

Much of the confusion evident in describing verbs as either stative or dynamic arises from the inability to distinguish between continuous and progressive aspects.

There is a distinction between, e.g.,
    I am thinking
and
    I think that ...
It is the distinction between the progressive aspect (I am thinking) and the continuous aspect with a simple verb form (I think).  In the second of these, the verb is akin to believe (i.e., a continuous state of mind) and in the first, it describes an ongoing (that is to say progressing) action or process.

For this reason, if no other, it makes sense to speak of stative vs. dynamic uses of verbs.

Even verbs which do not refer to mental states may be used in both senses so, for the picture above, for example, we might say:
    She sat down on the bench (active use)
    She sat on the bench for a while (stative use)
    She suddenly sat on the bench (active use)
    She was sitting on the bench (stative use)
    She was just sitting on the bench when she remembered what time it was (active use)
    I saw her sit on the bench (active use)
    I saw her sitting on the bench (either use depending on the context)

Many other languages make no such distinctions between these uses of verbs and the expressions I go and I am going or I think and I am thinking are indistinguishable.  English is not unique but it is slightly unusual.  In particular, the use of progressive forms of tenses is often determined by a verb's stative or dynamic meaning (not its form).  That is to say, the issue is semantic not grammatical.


3

The confusions between perfective, imperfective and perfect

There are three concepts here:

Perfective
napoleon
is the term used to indicate that an event or state is completed.  For example,
    Napoleon died in 1821
is a perfective form which may or may not have present relevance but is clearly finished.
    I went to Margate last Thursday
is another example of a perfective form in English.
    I have given up smoking
is also a perfective form (because the action is completed) which happens to be in the perfect aspect as well, in this case because it has direct relevance to the present.
The perfective can be contrasted with the ...
Imperfective
tennis
which is the term that indicates an event is not completed.  Examples are:
    She was playing tennis with John
    I have lived here all my life
In neither case is the event perceived as finished.  The form of the verb is described as imperfect.
Many languages, the European Romance languages among them, distinguish perfective and imperfective notions by alterations to the form of the verb.  The past tense forms in French, set out above, qualify for translation into English as imperfective forms, as was explained there.
Perfect
perfect
is the term used to signify an imperfective or perfective state or event which has a certain tense structure and carries a notion of the relativity of two events.
For example,
    I have been to America
is a perfective (the act of going to America has been completed) but is a perfect tense indicating that the past event is set in the present (and, therefore, has present relevance of some sort).
    I have lived here all my life
is imperfective (but still a perfect form) because it also signifies some present relevance (in this case that the state is probably (not certainly) current).
The perfect is, in English grammar, contrasted with the simple.

Many other languages, again, make no such distinctions between these uses of verbs and the expressions I went and I have been are indistinguishable.  English is not unique but it is slightly unusual.
Some languages are much clearer about perfective and imperfective forms.  For more on other languages, see the guide to aspect.


reading

Telicity: terminative, punctual and durative verbs

This is a related phenomenon in languages.
The term telic comes from the Greek, τέλος, meaning end.  The concept of telic and atelic verb phrases concerns whether an activity is seen as finished or unfinished.  To grasp the point, compare:

  1. I read the book for an hour
  2. I read the book in an hour

Sentence 1. suggests that I did not finished the book so the verb phrase is atelic: no end is in sight.
Sentence 2. suggests that I finished the book so the verb phrase is telic: the end point is clear.

This matters in English because we can say:
    I was reading the book for an hour
but we cannot have:
    *I was reading the book in an hour.

The implication for English grammar is that verbs in the perfect or continuous aspects are almost always possible with a time frame adverbial but not with a time span adverbial so.
A time frame refers to a period of time within which an action or event is set but a time span is simply a period of time with no indication of an event.
In other words, perfective forms, which are by definition telic, generally imply a time frame (even when it is not stated) but not a time span.  For example:
    I had been reading for an hour (for an hour refers to the time frame in which the reading occurred)
vs.
    *I had been reading in an hour (this is not possible because in an hour refers simply to a time span)
vs.
    I'll finish it in an hour
(where the time span is indicated but not the events which occur within it so it is not a time frame)
or
    I was cycling for a week
(time span)
vs.
    *I was cycling in a week (time frame)
or
    I have lived here for a year
(time span)
vs.
    *I have lived here in a year (time frame)
or
    I was reading when the telephone rang
(time frame)
vs.
    *I read when the telephone rang (time span)

The situation is complicated by the fact that verbs are generally telic or atelic depending on their meaning so the phenomenon of telicity is as much semantic as grammatical.  For example:

  1. I finished the book in an hour
    is telic by its meaning, because the adverbial refers to a time span, and
  2. *I finished the book for an hour
    is not possible because the adverbial refers to a time frame rather than a span.
  3. I was cooking when the telephone rang
    has the atelic verb cooking which is imperfective and the perfective rang which clearly had an end point so is telic.  Compare:
  4. I cursed when the telephone rang
    in which both verbs are telic and perfective.

Some languages, for example Finnish, Estonian, Czech and Hungarian, reserve a special verb form to signal telicity but English often does it through tense aspects with and without adverbials.

edge

A semantic issue

In some languages (notably Russian) a distinction is made in the form of the verb between those which are terminative and those which are durative.  English makes no such distinction in form but the concepts account for some of the stative / dynamic, perfective / imperfective and progressive / simple tense forms that can be used.  The use of the term concepts here, of course, implies that we are talking about meaning not grammar directly.  In other words the focus is semantic.

When terminative verbs which imply a change of state are used in progressive forms, they can be made durative so, for example, we can distinguish the sentences above as:
    She was peeling the potatoes
    They were opening the box
    I was sitting down

Terminative verbs which imply that an action cannot progress are less often used in this way and cannot usually be made durative so we do not usually encounter:
    *The glass was breaking
    *I was wishing her good morning
    *I was glancing at the clock

Durative verbs are commonly used in both the simple and progressive forms to imply continuous or progressive states.  For example:
    I lived in London at that time (continuous)
    She stayed in a guest house on holiday
(continuous)
    They were studying at university then
(progressive or continuous, i.e., an action or a background state)
    He was running in the park
(progressive)

Some terminative verbs can also be referred to as punctual or momentary verbs because their meanings cannot allow a durative interpretation.  This is, therefore, a semantic not a grammatical distinction.
These verbs include those which refer to instant events such as arrive, bang, begin, break, bump, burst, chop, crash, detonate, dip, dive, drop, explode, flash, glow, hit, jolt, kick, light, meet, name, open, pop, quip, rap, shatter, shoot, slam, smash, spit, spurt, steal, stop, tap, thump, upset, volunteer, wake etc.
For example:
    She is tapping on the window
cannot refer to a durative event because the verb itself is punctual or momentary.  The sentence can only be interpreted as iterative in aspect because the action is being repeated.
One the other hand:
    She is playing squash with her brother
is durative (and possibly prospective) and implies a progressive action rather than a momentary one.
Other examples include these pairs of sentences:

Progressive Iterative
The light is glowing The light is flashing
She was aiming She was shooting
The dog was growling The dog was barking
The rain is falling The rain is splashing

Some verbs are interpretable either way depending on the co-text and context so, for example:
    I am sitting on the train to London
almost certainly means that the action is durative and current (i.e., progressive) but:
    I am taking the train to work these days
almost certainly means that the action is repeated (i.e., iterative) and the adverbial, these days, reinforces that sense.

Verbs such as steal also live on the borders between punctual and durative meanings so they can work as punctual and as durative verbs depending on the context.  For example, we can have:
    He's stolen my pen
which is clearly a momentary event so
    He's been stealing my pen
makes little sense unless one believes that a pen can be stolen multiple times.  Make it plural (pens) and it works:
    He's been stealing my pens
clearly relates to an iterated event.
On the other hand,
    Someone's been stealing vegetables from my garden
is a possible punctual verb used iteratively.
The verb work shares this characteristic. so, for example:
    I've been working too much recently
strongly implies a series of working days rather than a single event.
All the speaking verbs, say, speak, talk and tell, work this way, too.

knock

An example of telicity and punctual vs. durative verbs in action

knock, knock  

To get this distinction really clear, you need to get the difference between the word continuous and the word continual.  The first refers to an unbroken state so, for example:
    The car makes a continuous growling noise
means that the noise is not interrupted but
    The car makes a continual growling noise
means that the noise comes and goes.
So, continuous means constant and continual means often repeated.

We'll take the examples of the punctual verb, knock. and a durative verb wear.  The first is a punctual verb because, by definition, the action is momentary and cannot be extended but it can be repeated.  The second is durative because, by definition, the action continues for some time.
So, if we say, e.g.:
    I knocked
we are clearly using the verb telically because we perceive that the action is completed (so it's also perfective).  Equally, if we say:
    I have knocked already
we know that this is a present tense message implying something like:
    So there's no need to knock again
or whatever and here, too, the meaning is perfective and telic because, by definition, the verb cannot be durative.  The verb is also telic, of course, because by its nature the action had an obvious end point in time.
A durative verb such as wear sends a very different message because:
    I have worn this coat a lot
can be interpreted as meaning that I am wearing it now so is durative in meaning extending from the past into the present and the immediate future.  In other words, the verb is atelic because no end point is recognisable to the hearer.
The time lines look like this:
telicity
in which the first one shows the current effect of the action and the second shows the durative nature of the verb wear.  In both cases, the yellow line is deliberately extended into the immediate future as well as the present because this perfect tense in English refers to the present in relation to the past, not the other way round.  That's why it's called the present perfect, of course.

Now, if we say:
    I have been wearing this coat a lot
we are not, fundamentally, changing the meaning which is signalled.  The time line will still be the same, to wit:
telicity2
and all we are doing is emphasising the duration of the verb.  That's not all it does because the use of a progressive also makes the idea of the action continuing into the future more emphatic.

However, if we try the same trick with the verb knock, we cannot use the same time line because:
    I have been knocking
must be represented with something like:
telicity3

in which it is clear that the use of a progressive form of a punctual verb results in an iterative aspect.  It also implies quite strongly that the knocking will go on.
In other words:

Simple use of a punctual verb = telic and perfective.
Progressive use of a punctual verb = atelic, imperfective and iterative.
Simple and progressive uses of durative verbs = atelic and imperfective.

If we want to signal an iterative aspect of a durative verb, the simple form + an adverbial (such as again and again, repeatedly, frequently, repetitively, continually, time after time etc.) is the only choice so we allow, e.g.:
    I have worn this coat again and again
However, we cannot signal iterative uses of a durative verb using the progressive form because:
    *I have been wearing this coat again and again
is not allowed (in English) although:
    I have been wearing this coat all year
means continuously, not continually (i.e. constantly, not repeatedly) so is fine.
With punctual verbs the case is altered because both:
    I have been knocking again and again
    I have knocked again and again

are both allowed although the use of the adverbial in the first case is unnecessary and the second form is slightly odd because English speakers would usually keep it simple and select the progressive form without the adverbial to convey the message.

English, of course, does not distinguish these senses structurally (although it often uses adverbials, as we see, to make the sense clear) but other languages sometimes do change the form to distinguish the meanings.  This is, of course a source of error for learners who may choose:
    I was hitting it with a hammer
when no iterative sense is intended.  This type of covert error is quite common.
The moral is that this matters in the classroom because if we try to teach tense forms without considering what sort of verb we are using, people will get confused and things wrong.
The distinction can be shows by presenting two different images like, e.g.:

anvil broken
He was hitting it with a hammer He hit it with a hammer

In the guides which are linked from here to present and past time, some attention to durative and punctual verbs will be given, especially in the guide to talking about the past because that is where the distinction is often important.


emc

Relative and absolute tense forms

Here, we depart slightly from a traditional description of tense forms in English and take a more functional view of what the forms actually do and the meanings they realise.

Absolute tense forms
These locate an event in time relative to the here and now, i.e., the time of speaking or writing.  For example:
    She will take the 6 o'clock train
sets her action as lying in the future from now.
    She caught the 6 o'clock train
sets her action in the past seen from now
    She is getting on the 6 o'clock train
sets her action in the present
    She was sitting on the train
sets the continuous state in the past
    She will be sitting on the train
sets the continuous state in the future
Relative tense forms
These take it a step further and relate what is happening relative to an absolute tense.  For example:
    She has caught the train and is working on her laptop
sets the present (working) in relation to a past event (getting on the train).  In other words, it embeds the past in the present.  The present has been altered by a past event because the implication is that she could not be working on her laptop had she missed the train.
    She had caught the train and was working on her laptop
sets the past (working) in relation to the pre-past (getting on the train).  In other words, it embeds the pre-past in the past.
    She will have finished by the time the train gets to London
sets the future (finishing) in relation to the post-future (getting to London).  In other words, it embeds the future in the post-future.
Relative tense forms do not stop there.  For example:
    She was sitting on the train, reading a book
is absolute in the sense that the events are fixed in time relative to the present as we saw above.
However,
    She was sitting on the train when she realised her mistake
sets the realising in relation to a background event and
    She had been going to work but had forgotten her laptop
sets the working as a future in the past (although one that did not happen).

An alternative way of seeing these forms is to consider what is being expressed in terms of time and the relationships between events and states, like this (following Lock, 1996: 149):

Time Example Explanation of the concept Visualised
green for present
orange for past
blue for future
The present in the present He is working in the garden The verb form refers to now set relative to now present in present
The past in the present He has worked in the garden The verb form refers to pre-now in relation to now past in present
The present in the past He was working in the garden The verb form refers to the present set in the past present in the past
The past in the past He had worked in the garden The verb form refers to the pre-past set in the past past in past
The present in the future He will be working in the garden The verb form refers to the present set in the future present in the future
The past in the future He will have worked in the garden The verb form refers to the past set in the future past in future
The future in the present He is going to work in the garden The verb form refers to the future set in the present future in present
The future in the past He was going to work in the garden The verb form refers to the future set in the past future in past

Seen this way, complex tenses which combine aspects can be explained conceptually.  Like this:

The visualisation in colour on the right of these tables appeals to some learners.  Do not present them all at once!

The page of example timelines to demonstrate some of the relationships set out here may help if you are considering teaching from this standpoint.  Click here to go there (new tab).


finite

Finite and non-finite forms

In these guides, we are mostly concerned with finite verbs forms (i.e., those marked in some way for person or tense).  There is a guide to finite and non-finite forms on this site.
It should not be forgotten that non-finite forms can also signal aspect, even if they do not signal time or tense.  For example:

Forms Meaning Aspects
Feeling rather shy, he put his hand up At the time he felt shy and at the time he put up his hand:
two processes, one continuous (the feeling) which is non-finite and one instant (the action) which is finite
continuous and simple
Being rather a tall man, he reached it easily Two verbs, one a permanent state (tall) which is non-finite , the other an action (instantaneous) which is finite continuous and simple
Arriving at station, he realised he was late Two simple actions (arriving and realised), the first non-finite and the second finite simple
If you will just hear me out Two verbs (one apparently future but actually present and referring to willingness) and finite, the other an infinitive (non-finite) simple


moving

Moving on

If the distinctions above are clear to you, it's time to look at the ways English refers to time and the speakers' perceptions of time.

To check that you have taken this on board, try two tests.


guides

Guides to times, tenses and aspects

In what follows this site takes a somewhat alternative view of tense grammar.

Many grammars, especially those aimed at students, start with the name of the tense, explain its formation and then list the ways in which it is used and the meanings we make with the forms.  It works along the lines of, e.g.:

The present progressive is formed by taking the appropriate present tense form of the verb to be, and following it with the -ing form of the verb (omitting a final 'e' if it is present) so we get, He is having lunch with his mother.
We use this tense to talk about current actions in progress, temporary states, the arranged future and ... etc.

That is familiar to most learners and teachers and may be reassuring.  However, it is a non-functional way to proceed.
It is non-functional because it presumes a mental process something like this:
mental process 1

Here, we are going to work the other way: we will start with the meanings we want to make and identify the major ways to make these meanings using verb forms and their aspects.
This assumes a mental process more like:
mental process 2

In these guides, the assumption is that you know (and can teach) how the tenses and aspects are formed because, as we saw above, English has a very simple set of inflexions and frequently none at all.
We are only considering meaning and function.

Here's the list.  Click on the area that interests you.

Talking about the Present Talking about the Past Talking about the Future Talking about Always Teaching tense and aspect


Reference:
Lock, G, 1996, Functional English Grammar, Cambridge: Cambridge University Press