Past Participles Definition
A) The Past Participle is used for all perfect forms of the verb:
eg: I have taken
eg: I had taken
eg: I will have taken
4 Conditional Perfect or the 3rd Conditional
eg: I would have taken
B) The Past Participle is used in the Passive with the verb 'To Be' in most aspects and tenses.
NOTE:
The Past Participle may also be used as an adjective.