Verbs

In English, a regular verb (EG: talk) has only two forms in the present tense; talk and talks
Singular Plural
1st person I talk we / you and I talk
2nd person you (singular) talk you (plural) talk
3rd person he, she, John, Lisa, the boy talks they / John and Mary / the girls talk
Only the verb to be has more than two forms in the present tense (am, is, are).
In the past tense, it is the only verb with more than one form (was, were). All other English verbs, regular and irregular, use just one form (talked, read, saw, etc.) for all persons.
In the future tense, English verbs show no subject-verb agreement whatsoever: I, you, he, we, they will do, speak, go, etc.

Auxiliary verbs

Auxiliary verbs are small verbs used to build verb chains.

Kate is speaking.

We had been asking.

She did like him once.

The auxiliary verbs are:

have when followed by a past participle:
e.g. have seen
be when followed by a present participle or by a past participle:
are working
are admired
do when followed by an infinitive:
do you think, do not think.
the modal verbs, which are generally followed by an infinitive:
will think, must be
Modal verbs

Modal verbs are auxiliary verbs that come in front of an infinitive (usually without to). They express such ideas as possibility, willingness, prediction, speculation, deduction, necessity and habit.

He must be angry

I can’t understand.

You ought to tell us.

Here are the main modal verbs:

will/would

may/might

dare

shall/should

must

need

can/could

ought

used to

Why be is always an auxiliary verb and possessive have sometimes is.

One of the main differences between auxiliary and main verbs is that auxiliaries are used in questions like Are you listening? and in negative sentences like You aren't listening. If we apply this as a test for auxiliary verbs, then other uses of be should also count as auxiliaries:

They are happy. Are they happy? They aren't happy.
He is your friend. Is he your friend? He isn't your friend.
It was here. Was it here? It wasn't here.
The same applies, for some people, to the verb have which means 'possess':

She has enough money. Has she enough money? She hasn't enough money.
Verb forms

The main verb forms (with examples from a regular verb) are these:

present tense

we walk

she walks



FINITE

past tense

I walked

imperative

Walk this way






NON-FINITE

present participle

I was walking

past participle

they have walked

infinitive

they can walk
they like to walk

Sometimes the word itself is the same – for example, walk can be present, infinive or imperative. But it’s important to be able to identify the different forms in use.

These six forms belong to two major groups, which play an important part in English grammar:

The present, past and imperative forms are finite.
The participles and the infinitive are non-finite.
Finite and non-finite verbs

If an ordinary sentence contains just one verb, this verb will be finite. (Why 'finite'?)
This is [finite] a finite verb.

In a verb chain, the first verb in the chain is almost always finite, and the other verbs are always non-finite.
They have [finite] looked [non-finite] at it

The finite verb in a clause defines the way the clause works. It gives key information about:

who is doing the thing - i.e. the subject:
e.g. They have ... but: She has ...
and when it is being done - i.e. the tense:
e.g. They have ... but: They had ...
Non-finite verbs are not restricted in these ways, though they are restricted in other ways. For example, the infinitive have can be used for any time and any subject:

He seems to have a cold. (present time, singular subject)

They seemed to have colds. (past time, plural subject)