Khan Academy : Verbs!

irregular verb

A verb in which the past tense is not formed by adding the usual -ed ending.

linking verb

A verb that does not show action but connects the subject with a word in the predicate.

auxiliary(helping) verb

Helping verbs are verbs that help the main verb in a sentence by extending its meaning.

verb

An action word.

modal verbs

An auxiliary verb that expresses necessity or possibility.

Progressive perfect verb aspect

Any verb (in the past, present or future) in the perfect progressive tense.

progressive verb aspect

Progressive aspects are used to describe actions that happen over an extended period of time.

perfect verb aspect

The perfect aspect (or complete aspect as it's sometimes called) is the aspect of a verb which expresses a completed action.

simple verb aspect

The simple aspect includes all verbs in the simple tense (past, present, or future).

verb agreement

The subject and verb must agree in number: both must be singular, or both must be plural.

verb tense

Verb that tells the time of the action or being.