In English, verbs are words that indicate action or existence.

Every sentence must have a main verb to be a complete sentence. The verb is part of the predicate of a sentence.

In English, most verbs have 4, 5, or 6 forms. The exception is the verb to be, which has 9 forms. The base form of the verb is the form it takes in the simple present tense (except third person singular.) Again, the exception is the verb to be. The base form for to be is be. We only use the base form, be, in the infinitive form (to be.) The infinitive form is the base form with the preposition to in front of it.

Examples:

Sentence	Base verb	Form
I am a teacher.	be	am (simple present tense, 1st person singular)
They danced all night.	dance	danced (simple past tense)
She had sung three songs for him.	sing	sung (past participle)

Here are links to good information about verbs. Try looking at different pages on the same topic. It will give you more opportunities to understand and practice. (Each link opens in a new page.)

A good overview of all the tenses and how they are different. Lots of excercises. (englishpage.com)

Another good overview of the tenses. (leo.stcloudstate.edu)

A long, but good, description of all the tenses (writingcentre.uottawa.ca)