现在完成时:按要求改写下列各句
问题描述：
现在完成时:按要求改写下列各句
4.They have bought a computer.(改成否定句)
_________________________________________
5.He has lost his book.
(先改成一般疑问句,再作肯定与否定回答)
_________________________________________
答
4.They haven't bought a computer.
5.Has he lost his book?Yes,he has.No,he hasn't