раскройте скобки , заменяя инфинитив нужной формой глагола -сказуемого 1"When you (to have) breakfast yesterday ?" 2"I (to have) breakfast at nine in the morning"
When did you have breakfast yesterday? (окончание не надо т.к. это вопрос)
I had breakfast at nine in the morning.
When did you have breakfast yesterday? I had breakfast at nine in the morning