Question

should have done和shouldn't have done，couldn't have done是什么意思

Answer 1

"should have done" 和 "shouldn't have done" 是英语中表示对过去行为的评价或建议的短语。

"should have done" 表示对过去的行为提出建议或指责，意思是在过去的某个时间点，某人本应该做某事，但事实上没有做。它表示对过去行为的后悔或建议。

例如：

I should have studied more for the exam.（我本应该更多地为考试学习。）
He should have listened to her advice.（他本应该听她的建议。）

"shouldn't have done" 表示对过去的行为提出批评或指责，意思是在过去的某个时间点，某人本不应该做某事，但事实上做了。它表示对过去行为的后悔或批评。

例如：

She shouldn't have eaten so much junk food.（她本不应该吃那么多垃圾食品。）
They shouldn't have ignored the warning signs.（他们本不应该忽视警告信号。）

总结起来，"should have done" 表示对过去行为的建议或后悔，而"shouldn't have done" 表示对过去行为的批评或后悔。

Answer 2

should
have
done
本该做到但是没有做到
如:
you
should
have
won
the
game,but
you
failed.
你本该赢了那场比赛,但是你输了.
shouldn't
have
done
本不该做的而做了
如:
you
shouldn't
have
watered
the
flowers.
你本不该浇花的
could
have
done
本可以做而没有做
如:
you
could
have
worked
out
the
question,but
you
didn't
你本该解出拿到题的,但是你没有
couldn't
have
done
就不要我说了吧
类推~~~

Answer 3

should
have
done:本应该做某事却没做
shouldn't
have
done:本不应做某事却做啦
could't
have
done
：（表推测）不可能做了某事
以上都是虚拟语气