Most verbs are regular in English and they form their past tense and past participles by adding a -d or an -ed to the end of the verb.
If a verb does not follow this rule, it is considered irregular and students need to study in order to learn the form. Click on the following link if you want to see some fairly common irregular verbs.
If you want to do an exercise on irregular verbs you may want to go to:
If you want to do an exercise where regular and irregular verbs are used in passive you may go to: