This article introduces at the 3 main verb forms a verb can take: the infinitive, the present participle and the past form.
The Infinitive is the base form of a verb. These are infinitives:
love, eat, walk, be
In English, the infinitive is nearly always the same as the present tense. The only exception is the verb be:
I love, I eat, I walk, I am
Note that some grammars regard the infinitive as to + base form; in this grammar guide the infinitive is without the to. This is called the bare infinitive.
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 love she loves
I eat he eats
I walk it walks
The Present Participle
We make the Present Participle of regular verbs by adding –ing to the end of the bare infinitive:
The gerund has the same form as the present participle. Both the present participle and the gerund are known as the -ing form.
The Past Form
When we talk about the past, we use the past tense 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 love – I loved – loved
I walk – I walked – walked
In regular (and many Irregular) verbs, the past participle is the same as the past form.
Verbs in English Grammar – a good introduction to verbs in general.
Verb Tenses & Forms in English Grammar – a look at all the tenses and forms a verb can take.