For details of these rules, see English verbs.
For details of their meanings and usage, see English modal verbs.
A regular English verb has only one principal part, from which all the forms of the verb can be derived.
Most English verbs have six inflected forms (see the table), but be has eight different forms.
Dowty gives some tests to decide whether an English verb is stative.
In regular English verbs, the past tense and past participle have the same form.
For full details of past tense formation, see English verbs.
For other uses of constructions with would and should, see English modal verbs.
For other meanings of would have and should have, see English modal verbs.
Most English present verbs are regular and have only one change in ending (-s for third person singular).