Your word simple is throwing me off. Past of buy - bought.
Bought isthe simple past and past participle of "buy".
The simple past tense and past participle forms are both bought.
It is simple past tense.
The simple past is had.
The past simple of "have" is "had."
Past simple and simple past are both the same thing. They are both the past tense of a verb.
The simple past tense is climbed.
The simple past and past participle are both 'had'.
The simple past and past participle are both brought.
The past simple of "study" is "studied."
"Listened" is the past simple of "listen" as well as the past participle.