Irregular Verbs
The way a verb forms its past tense determines whether it is regular or irregular. A
regular verb has the –d or –ed ending to show the past tense. Irregular verbs do not have
the –d or –ed ending. They are modified in various other ways to indicate past tense.
Regular
believe → believed
smile → smiled
Irregular
run → ran
eat → ate
An irregular verb forms its past and past participle by
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Principal Parts of Verbs
Every verb has four basic parts, which are called its principal parts. You must know all
of these in order to form the different tenses correctly.
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Present (aka Infinitive) – existing or happening now
know
to know
take
to take
write
to write
Present Participle The present participle of a verb always ends in –ing.
knowing
taking
writing
Past – existed or happened in the past
knew
took
wrote
Past Participle The past participle of a verb always requires a helping verb (have, has, had).
had known
have taken
has written