Verb Forms

From The ICAL TEFL wiki

The Infinitive is the base form of a verb. These are infinitives:

In English, the infinitive is nearly always the same as the present tense. The only exception is the verb be:

Note that some grammars regard the infinitive as to + base form; in this grammar guide the infinitive is without the to.

When we use he, she or it in the present tense, regular verbs add -s to the end. This is the third person singular:

I have	she has
I go	he goes
I walk	it walks

We make the Present Participle of regular verbs by adding -ing to the end of the infinitive:

be	being
have	having
go	going
walk	walking

The gerund has the same form as the present participle. Both the present participle and the gerund are known as the -ing form.

When we talk about the past, we use the past form of the verb (this does not change for the third person singular). To make the past form with regular verbs, we add -ed:

today	yesterday	past participle
I walk	I walked	walked
I cry	I cried	cried

In regular (and many irregular) verbs, the past participle is the same as the past form.