The INFINITIVE form of a verb is the form which follows to:
to ask to believe to cry to go
to protect to sing to talk to wish
This form is indistinguishable from the base form. Indeed, many people cite this form when they identify a verb, as in "This is the verb to be", although to is not part of the verb.
Infinitives with to are referred to specifically as TO-INFINITIVES, in order to distinguish them from BARE INFINITIVES, in which to is absent:
To-infinitive
Bare infinitive
Help me to open the gate
Help me open the gate
4.4 More Verb Forms: -ing and -ed
So far we have looked at three verb forms: the present form, the past form, and the infinitive/base form. Verbs have two further forms which we will look at now.
[1] The old lady is writing a play [2] The film was produced in Hollywood
The verb form writing in [1] is known as the -ing form, or the -ING PARTICIPLE form. In [2], the verb form produced is called the -ed form, or -ED PARTICIPLE form.
Many so-called -ed participle forms do not end in -ed at all:
The film was written by John Brown The film was bought by a British company The film was made in Hollywood
All of these forms are called -ed participle forms, despite their various endings. The term "-ed participle form" is simply a cover term for all of these forms.
The -ed participle form should not be confused with the -ed inflection which is used to indicate the past tense of many verbs.
We have now looked at all five verb forms. By way of summary, let us bring them together and see how they look for different verbs. For convenience, we will illustrate only the third person singular forms (the forms which agree with he/she/it) of each verb. Notice that some verbs have irregular past forms and -ed forms.
Base/Infinitive Form
Present Tense Form
Past Tense Form
-ing Form
-ed Form
cook
he cooks
he cooked
he is cooking
he has cooked
walk
he walks
he walked
he is walking
he has walked
take
he takes
he took
he is taking
he has taken
bring
he brings
he brought
he is bringing
he has brought
be
he is
he was
he is being
he has been
Finite and Nonfinite Verbs
Verbs which have the past or the present form are called FINITE verbs. Verbs in any other form (infinitive, -ing, or -ed) are called NONFINITE verbs. This means that verbs with tense are finite, and verbs without tense are nonfinite. The distinction between finite and nonfinite verbs is a very important one in grammar, since it affects how verbs behave in sentences. Here are some examples of each type:
Tense
Finite or Nonfinite?
David plays the piano
Present
Finite
My sister spoke French on holiday
Past
Finite
It took courage to continue after the accident
NONE -- the verb has the infinitive form
Nonfinite
Leaving home can be very traumatic
NONE -- the verb has the -ing form
Nonfinite
Leave immediately when you are asked to do so
NONE -- the verb has the -ed form
Nonfinite
Auxiliary Verbs
In the examples of -ing and -ed forms which we looked at, you may have noticed that in each case two verbs appeared:
[1] The old lady is writing a play [2] The film was produced in Hollywood
Writing and produced each has another verb before it. These other verbs (is and was) are known as AUXILIARY VERBS, while writing and produced are known as MAIN VERBS or LEXICAL VERBS. In fact, all the verbs we have looked at on the previous pages have been main verbs.
Auxiliary verbs are sometimes called HELPING VERBS. This is because they may be said to "help" the main verb which comes after them. For example, in The old lady is writing a play, the auxiliary is helps the main verb writing by specifying that the action it denotes is still in progress.