虚拟语气中would could should might have done与had done都是表示过去,在用法上有

虚拟语气中would could should might have done与had done都是表示过去,在用法上有 情态动词中 should might could would + have done 与 它们在if 虚拟语气中用法 有 虚拟语气could/should/would/might +have done 用法的差别? 虚拟语气中had done与would have done,did与would do 的用法有何区别 虚拟语气中的would/conld/should do/have done 与 did/had done有何区别 虚拟语气 should have done 与 could have done 虚拟语气,与过去事实相反 :从句 :had + 过去分词 主句 :would/ should/ could/ might could have done 表示过去有必要做某事却未做 could not have done没有虚拟语气的用法,只 对过去事实的虚拟中的:would /could / should /might + have done 有什么区别? 英语虚拟语气在表和过去事实相反时, 从句谓语had done 主句谓语 would/could have done 问题 请问could not have done/might not have done可用于虚拟语气中吗 区别could,might,would,should have done