Start is a regular verb so you add -ed to make the past tense = started
Compare this with irregular verbs their past tense is not made by adding -ed they have another word or sometimes the same word.
eg cost - past is cost. Run - past is ran. See - past is saw.
Start is a regular verb; therefore, its past tense is started.
The past tense of the verb "start" is "started."
The past tense of "do" is "did."
By is not a verb and does not have a past tense. Buy is a verb, and the past tense is bought.
The past-tense verb for "be" is "was" or "were" depending on the subject.
The past tense of the verb 'am' is 'was' or 'were.' The verb 'am' is derived from the verb 'to be.'
"Shook" is the past tense of the verb, "to shake".
The past tense of the verb "promise" is "promised."
Slept is the past tense of the verb sleep, so there is no past tense for it.
Inactive is not a verb and does not have a past tense. Inactivate is a verb, and the past tense is inactivated.
The past tense of the verb "lead" is "led".
The past tense of the verb 'pull' is 'pulled'.