A book was bought by John.
John bought a book is the simple past tense.
"Had bought" is past tense. It should be used when talking about something that was purchased in the past. "He had bought the book but lost it on the train." "Have bought" is present tense. "I have just bought this book and can't wait to read it."
The past and past participle for "buy" is "bought."
infinitive: buy past: bought past participle: bought
The past participle of buy is bought.
"Bought" is the past tense of "buy".
Bought isthe simple past and past participle of "buy".
"Bought" is the past tense of the verb "to buy".
The past tense is bought.
infinitive: buy past: bought past participle: bought
The past particle of "buy" is "bought".
The past indicative and past participle of "buy" are both "bought".