, _I talk, I
talked, I shall talk_, etc. Verbs also vary to indicate completed
or incompleted action; as, _I have talked, I shall have talked_,
etc. To these variations, which indicate the time of the action,
the name TENSE is given.

The full verbal statement may consist of several words; as, _He
MAY HAVE GONE home_. Here the verb is _may have gone_. The last
word of such a verb phrase is called the PRINCIPAL VERB, and the
other words the AUXILIARIES. In the sentence above, _go (gone)_
is the principal verb, and _may_ and _have_ are the auxiliaries.

50. In constructing the full form of the verb or verb phrase there
are three distinct parts from which all other forms are made. These
are called the PRINCIPAL PARTS.

The First Principal Part, since it is the part by which the verb is
referred to as a word, may be called the NAME-FORM. The following
are name-forms: _do, see, come, walk, pass_.

The Second Principal Part is called the PAST TENSE. It is formed
by adding _ed_ to the name-form; as, _walked, pushed, passed_.
These verbs that add _ed_ are called Regular Verbs. The verb form
is often entirely changed; as, _done (do), saw (see), came (come)_.
These verbs are called Irregular Verbs.

The Third Principal Part is called the PAST PARTICIPLE. It is used
mainly in expressing completed action or in the passive voice.
In regular verbs the past participle is the same in form as the
past tense. In irregular verbs it may differ entirely from both
the name-form and the past tense, or it may resemble one or both
of them. Examples: _done (do, did), seen (see, saw), come (come,
came), set (set, set)_.

51. THE NAME-FORM, when unaccompanied by auxiliaries, is used with
all subjects, except those in the third person singular, to assert
action in the present time or present tense; as, _I go, We come,
You see, Horses run_.

The name-form is also used with various auxiliaries (_may, might,
can, must, will, should, shall_, etc.) to assert futurity,
determination, possibility, possession, etc. Examples: _I may go,
We shall come, You can see, Horses should run_.

By preceding it with the word _to_, the name-form is used to form
what is called the PRESENT INFINITIVE; as, _I wish to go, I hope
to see_.

What may be called the S-FORM of the verb, or the SINGULAR form,
is usually constructed by adding _s_ or _es_ to the name-form.
The s-form is used with singular subjects in the third person; as,
_He goes, She comes, It runs,