21．—My dog's really fat.
—You ________ have given her so much food.
A．wouldn't B．can't
C．shouldn't D．mustn't
答案与解析：C 句意：——我的狗真的肥了。——你不应该喂她那么多食物。shouldn't have done sth.表示过去不应该做某事而实际上却做了。
22．—The head teacher said we had only three days to finish the project.
—Don't worry. We have already ________ two thirds of it.
A．taken over B．got through
C．made up D．given away
答案与解析：B get through此处意为“做完；完成”，符合句意。take over“接管；接收”；make up“编造；弥补；虚构”；give away“泄漏”。
