A past participle is used to indicate the past or a completed action or time. it is formed by adding "-d" or "-ed", to the base form of regular verbs, but can be formed in other ways for irregular verbs.
For example, in the sentence 'I have swallowed a button', swallowed is a past participle of the regular verb "swallow".
Examples of how the past participle is formed for irregular verbs are as follows:
| Base form | Past participle |
| know | known |
| eat | eaten |
| become | become |
| fly | flown |
There are no hard-and-fast rules for the past participle of irregular verbs, unfortunately, which means that their various forms have to be memorised.
The past participle can be used as follows:
- Participial phrases
- Based on the results of the examination, Mark changed his plans.
- Participial adjectives
- The teacher was determined to finish the chapter.
- Using the perfect tenses
- I have stayed there many times before.
- using the passive voice
- The shop was closed by the time we arrived.