1．By the time the firefighters arrived, the fire ____________(burn) out.
答案：had burnt
2．She entered the room，____________(turn) on the light and found everything stolen.
答案：turned
3．If he ____________(follow) my advice, he would have succeeded.
答案：had followed
4．Hardly had he ____________(begin) to speak when the audience interrupted him.
答案：begun
