Question

shouldn't have done couldn'd have done should have done could have done 他们的意思到底 实际有没有做

Answer 1

1.should
have
done
本应该做而实际未做，表示后悔的虚拟语气。
2.shouln't
have
done
本不应该做而实际做了。如：he
was
very
sad
now.
I
shouldn't
have
scolded
him.
3.could
have
done
表示本可以（有能力）做，而实际未做。I
could
have
finished
my
work
on
time,
but
I
wasted
a
lot
of
time
chatting
on
line.
4.couldn't
have
done
与前三者不一样，不表示后悔，责备的语气。而表示比较肯定的猜测语气，翻译为：（过去）不可能做。如：Tom
couldn't
have
broken
the
window,beause
he
was
watching
TV
at
home
at
that
moment.

Answer 2

你好！
在modal
verb後加n't通常都是否定的意思
例如you
should
do
your
homework
意思是你应该做家课
但如果should後加n't
即shouldn't
变成you
shouldn't
do
your
homework
意思变成完全相反
即你不应该做家课
希望对你有所帮助，望采纳。

Answer 3

这和他们到底有没有做 没有关系，有可能做了 有可能没做
这就是表示 你对 之前情况的推测。

我说 你今天迟到了，你应该是睡过头了/你可能是睡过头了。 谁能通过我说的这句话 判断出你是实际睡过头了没。