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英语高考语法解析第七节情态动词和虚拟语气情态动词+have done用法 must have done一定做过某事,其否定形式为can't/couldn't have done can/could have done 1
could (不能用 can) have done 表示“过去本能够做某事却未做.”注意:其否定形式 couldn't have done 没有虚拟语气的用法,couldn't have done 只能表推测,相当于 can't have
c o u l d ( bu neng yong c a n ) h a v e d o n e biao shi “ guo qu ben neng gou zuo mou shi que wei zuo . ” zhu yi : qi fou ding xing shi c o u l d n ' t h a v e d o n e mei you xu ni yu qi de yong fa , c o u l d n ' t h a v e d o n e zhi neng biao tui ce , xiang dang yu c a n ' t h a v e . . .
could have done 是英文中常见的句型,不一定是虚拟语气哦!有两种基本含义: 1.表示主观猜测: 即对已经发生动作或已经存在的状态作出主观上的猜测,通常可译为“
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虚拟语气，很重要的使用场景：针对已经发生的事，假设当初做了其他的决定，或其他客观条件发生了变化，那么就会出现和现在不一样的结果。这种场景用would/could/might/should have
couldn't have done是虚拟语气，表达与过去的事实相反。例句： If I hadn't been told，I couldn't have known this. 假如别人不告诉我，我就不会知道这件事。If you hadn't study
couldn't have done和can't have done都表示不可能,是对过去情况的推测。例句:He can't / couldn't have worked out the problem.他不可能解决了这个难题。can't
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can/could have done 过去可能已经做了某事;can`t/couldn`t have done过去不可能做某事 但这四个短语中,might have done还有特殊用法,即虚拟:过去本可以做而没有做; could have don
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could have done 本可以做而没有做， 能做而没有做
↓。υ。↓ shuld have done 1。本应该做而没有做；2。
couldn`t have done 不用于虚拟语气 么couldn`t have done 不用于虚拟语气 那要是说 本不能够做..怎么表达 答案 couldn't have done1.对过去情况推测,表示:不可能做了某事比
