Irregular verbs form the past participle and the past form without "-(e)d" or "-t", and frequently their past form and past participle are different. For example, the past form of the verb "break" is "broke" and the past participle is "broken."
This list contains the most common verbs that form their past tenses irregularly:
Table: English Irregular Verb Chart [Quick Reference]
Tip: print or photocopy this table as a quick reference