The past participle of a verb is a verb ending in -ed that acts as an adjective or an adverb.
For example:
The clear blue sky seemed to turn into a darkened cloud once winter began.
Therefore, the past participle of happen is happened.
The past participle of "happen" is "happened."
The past participle of the word "have" is "had."
The past participle of the word "do" is "done."
The past participle of the word "Find" is the word "Found."
The past participle of the word "pick" is "picked".
The past participle of the word "finish" is "finished."
The past participle of the word "pick" is "picked".
The past participle of the word "have" is "had."
The word "it" does not have a past participle as it is a pronoun. It is only verbs that have a past participle.
Happen is not a participle. It is the simple present tense. The present participle is happening, and the past participle is happened.
The past participle of the verb to have is had.
The past participle of the word "do" is "done."
The past participle of the word "Find" is the word "Found."
The past participle of the word graduate is graduated
The past participle of the word 'fall' is 'fallen'.
The word "invited" is the past participle of invite.
The word 'worse' is an adjective so doesn't have a past participle. Only verbs have a past tense/past participle.
The past participle is planned.