1.Don't take his remarks so seriously.He is so upset that I don't think he really knows what____
A he said B.he'd said c.he's saying d.he says
但是为什么不能用D?
2.Roman Empire _______ for centuries.
A.has existed B.existed C.had existed D.was existing
但是for+一段时间为什么不是用完成时?
3."What's wrong with your coat?"
"Just now when I wanted to got off the bud the man next to me ___on it."
A.sat B.was sitting C.had been sitting D.had sat
但是如果是要强调一直坐在他的外套上为什么不能用过去进行时?
4.Great efforts to increase wheat production must be made if bread shortage___avoided.
A will be B can be C.were to be D.is to be
为什么?