Irregular verbs do not follow the normal patterns for tense and past participle. While most English regular verbs use the ending “-
ed” for the past tense and participle forms, irregular verbs each have their own unique tense forms and past participles.
This is the exercise involving Irregular Verbs in the past participle tense.
The past participle is also used with "had/have" to form the past perfect tense.
Example:
We have kept this secret for many years.
I've given some money to John.