couldn't have done和can't have done都表示不可能,对过去情况推测
比如He can't / couldn't have worked out the problem.他不可能解决了这个难题.
can't 也可以用于对现在情况推测.He can't be very smart
couldn't 不行.
couldn't have done可以用于 和过去事实相反的虚拟语气,can't have done 不行
比如：If you hadn't gone to the party,you couldn't have met your future wife.
如果你没去晚会,你不可能遇到你未来的妻子.
喜欢的话,