An irregular verb is one that does not form its simple past tense or its past participle by adding "-ed" or "-d" to the base form. Irregular verbs contrast ...
– give / forgive (given / forgiven) – come / become (come / become) – stand / understand (stood / understood) A few verbs don’t change at all. For example: read – read – read (the pronunciation changes from the present /reed/ to the past tense and past participle /red/ cut – cut – cut (no pronunciation change)
The past forms for irregular verbs are not regular -- you just have to learn them. Sometimes people study these verbs in groups based on the past simple form -- ...
Taking some time to make sentences using each irregular verb form will help you to use these verbs ... Base Form, Past Simple (V2), Past Participle (V3) ...