题目内容
18.-Is this computer working well now?-Yes.My mother _______ it repaired.( )
A. | need have had | B. | can have had | C. | must have had | D. | should have had |
分析 -这台电脑现在运转正常吗?
-是的.我妈妈肯定已经把它修好了.
解答 答案:C.根据Yes可知电脑现在运转正常,所以电脑肯定已经被修理了,因此用must have done 表示"肯定做过某事",所以答案是C.其他选项的含义分别是A项一般不用,need一般用否定,needn't have done 表示"本不必做";B表示"可能做过某事";D表示"本应该做而没有做".
点评 考查情态动词.情态动词的完成式.
1.must+have done:用于肯定句,表示推测,意为"一定(已经)…".
2.can+have done:用于否定句或疑问句,表示推测,意为"可能(已经)…".
3.could+have done:可用于肯定句、否定句或疑问句,表示推测、责备或遗憾等,意为"可能…"、"本来可以…"、"本来应该…"等.
4.should[ought to]+have done:可用于肯定句、否定句或疑问句,表示责备或遗憾等,意为"本来应该…".
5.need+have done:用于否定句或疑问句,用于否定时意为"本来不必",用于疑问句时意为"有必要…吗".
6.may+have done:用于肯定句或否定句,表示推测,意为"可能(已经)…".
7.might+have done:用于肯定句或否定句,表示推测,意为"可能(已经)…(此时 might 可换为 may);另外还可以表示过来可能发生的事结果未发生,意为"本来会…"(此时 might 不能换为 may).
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