1. Grammar Handbook: Regular and Irregular
Verbs
Verbs are subdivided into two groups, regular verbs and irregular
verbs, on the basis of how their past tense and past participles are
formed. See below for tips on how to distinguish between them.
Regular Verbs
Most verbs are regular verbs. Regular verbs are those whose past
tense and past participles are formed by adding a -d or an -ed to
the end of the verb.
"To roll" is a good example of a regular verb:
roll, rolled, rolled
Sometimes the last consonant must be doubled before adding the -
ed ending. For example:
plan, planned, planned
Irregular Verbs
There is no formula to predict how an irregular verb will form its
past-tense and past-participle forms. There are over 250 irregular
verbs in English. Although they do not follow a formula, there are
some fairly common irregular forms. Some of these forms are:
break, broke, broken
cut, cut, cut
run, ran, run
meet, met, met
come, came, come
repay, repaid, repaid
swim, swam, swum
be was/were been
Distinguishing Regular and Irregular Verbs

2. Dictionaries are perhaps the most valuable tool one can use in
distinguishing between regular and irregular verbs. If only one form
of the verb is listed, the verb is regular. If the verb is irregular, the
dictionary will list the principal parts of the other forms.