Irregular verb and Termination "ed"

An irregular verb is one that does not take the -ed ending for the Past Simple and Past Participle forms. Some irregular verbs do not change.

Example:

• cost - cost - cost
• cut - cut - cut

while others change completely.

Example:

• buy - bought - bought
• break - broke - broken
• be - was/were - been                                  

List of irregular verb:

Irregular verb in the classroom...

Exercises:

•  http://www.englisch-hilfen.de/en/exercises_list/verbs.htm 
• http://www.ego4u.com/en/cram-up/grammar/irregular-verbs