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情态动词+have done的用法 must have done sth.一定做某事 can/could have done sth.本来能够做某事，而实际上未做 can't/couldn't have done sth.不可能做过某事 ought to/should have done sth.过去本应该做某事而实际上并没有做 (责任编辑：admin) |
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情态动词+have done的用法 must have done sth.一定做某事 can/could have done sth.本来能够做某事，而实际上未做 can't/couldn't have done sth.不可能做过某事 ought to/should have done sth.过去本应该做某事而实际上并没有做 (责任编辑：admin) |