The past tense of buy is bought.
By is not a verb and does not have a past tense. Buy is a verb, and the past tense is bought.
infinitive: buy past: bought past participle: bought
The past tense of buy is bought.
The past participle of buy is bought.
The past continuous tense of buy is:I/He/She/It was buying.You/We/They were buying.
"Bought" is the past tense of the verb "to buy".
The past tense is bought.
The past tense is: You bought cake.
buy -- I buy my lunch everyday buys -- She buys her lunch on Wednesdays am/is/are buying -- We are buying our lunch today
Buy is present tense. Buying is the present participle. The past and past participle is bought.
This sentence is already in the past tense. "Went" is the past tense of the verb "go".