mustn't be done的含义
发布网友
发布时间：2022-09-22 22:46
共3个回答
热心网友
时间：2024-07-06 16:42
详细点就是说：1）mustn't
have
done可意为“本不必”，即已经做了某事，
而实际上不必要
2)首先have
done表示已经做过，这点就不用谈了。
can't
have
done
表示以前不可能做某事。
例句
---where____margaret
have
put
the
empty
bottles？
---she________them
away.they
must
be
somewhere.
a.can;can't
have
thrown
b.must;must
have
thrown.
c.must;needn't
d.can;must
throw
答案为a.第一个句子是一个疑问句而且表示可能性的推测，所以只能用情态动词can或could，第二句的答语表示对过去的推测，所以用can't
have
done.
请看常见的“情态动词
+
have
+
过去分词”的用法：
一、“must
+
have
+
过去分词”表示对过去发生的事情或状态进行推测，语气比较坚定，通常只用于肯定句。如：
it
must
have
rained
last
night,
for
the
ground
is
wet.
you
must
have
been
mad
to
speak
to
the
servant.
二、“can
/
could
+
have
+
过去分词”表示对过去某种情况的怀疑或不确定。can和could一般用于否定句和疑问句，could的语气较can弱。如：
i
didn't
see
her
at
the
meeting
this
morning;
she
can't
/
couldn't
have
spoken
at
the
meeting.
he
can't
have
finished
the
work
so
soon.
热心网友
时间：2024-07-06 16:43
be
done意为“禁止/不能被...”，可用于将来时；mustn't
have
been
done是现在完成时，表示到说话时为止（或到现在为止）已经发生或完成了（不一定结束）的动作或状态，也就是过去发生的动作，而根据这道题目，他现在睡着了，不能被打扰，应该是将来的动作，所以矛盾了。正确答案是“mustn't
be
disturbed”。谢谢！
热心网友
时间：2024-07-06 16:43
be
disturbed".
首句看的"now"是说他现在正在睡觉,所以后句是"他不可以被打扰",应填"mustn't
be
disturbed"
"mustn't
have
been
disturbed"意思是表示"他过去不可以被打扰".
