There's no light on.they____be at home.A:can't B:mustn't C:needn'_英语解答

There's no light on.they____be at home.
A:can't B:mustn't C:needn't D:shouldn't
为什么用can't,而不用mustn't.mustn't不是表推测吗?

人气：281 ℃　时间：2019-11-17 02:15:45

解答

can't 是用于否定的推测.而must是用于肯定的推测的,mustn't用于关于禁止,不允许内容的句子.
1.That must be him.He said he would come yesterday.
2.That can't be her.She has gone to London.