根据要求进行句型转换（每空1分）
小题1:Tom was playing the piano when Mary bought a drink. (同义句转换)
While Tom _________ _________ the piano, Mary ___________ a drink.
小题2:Peter cut himself in the accident. (改为否定句)
Peter ______ ________ himself in the accident.
小题3:Why don’t you wait for us at the gate? (改为同义句)
________ __________ wait for us at the gate?
小题4:Emily was reading a book when the light went out. (对划线部分提问)
_______ _______ Emily _______ when the light went out?
小题1:was playing bought
小题2:didn’t cut
小题3:Why not
小题4:What was doing
题目分析：
小题1:题干的意思是：玛丽买饮料时，汤姆在弹钢琴。也就是说：汤姆弹钢琴时，玛丽买了饮料。所以其同义句为：While Tom was playing the piano, Mary bought a drink.。
小题2:题干的意思是：彼得在事故中割伤自己。此句用的是一般过去时，所以我们可以借助助动词did将其变为否定句：Peter didn’t cut himself in the accident.
小题3:题干的意思是：你为什么不在门口等我们吗？Why don’t you do sth？="Why" not do sth？所以可将其更为：Why not wait for us at the gate?
小题4:题干的意思是：艾米丽正在读一本书时，灯熄灭了。划线部分reading a book表示活动，对其提问可以以what引起问句。即What was Emily doing when the light went out?