Most past particples are the same as the simple past form, usually made by adding '-ed' to the end of the verb.
| Verb | Simple Past | Past Participle | |
|---|---|---|---|
| Look | I looked | I have looked |
 |
| Walk | I walk | I have walked |
 |
| Read | I read | I have read |
 |
| Cook | I cooked | I have cooked |
 |
However, there are many verbs that don't follow this rule. These are called irregular past participles. Here are some examples of the most commonly used irregular verbs.
| Verb | Simple Past | Past Participle | |
|---|---|---|---|
| eat | I ate | I have eaten |
 |
| be | I was / were | I have been |
 |
| take | I took | I have taken |
 |
| see | I saw | I have seen |
 |
| get | I got | I have gotten |
 |
| buy | I bought | I have bought |
 |
| begin | I began | I have begun |
 |
| choose | I chose | I have chosen |
 |
| ride | I rode | I have ridden |
 |
| know | I knew | I have known |
 |
| go | I went | I have gone |
 |
Irregular past participles are used the exact same way as regular past participles are.