英语选择题（情态动词）——Look ,the light in the teacher's office is still on .Mr.Brown is working there .He always works late at night.—— It ___be Mr.Brown .He's gone to Hawaii on vacation.A.can't B.mustn't C.may D.must ,为什么?
问题描述：
英语选择题（情态动词）
——Look ,the light in the teacher's office is still on .Mr.Brown is working there .He always works late at night.—— It ___be Mr.Brown .He's gone to Hawaii on vacation.
A.can't B.mustn't C.may D.must
,为什么?
答
选A，must表示肯定推测，否定推测肯定不应该是can not。must not表示禁止。
答
A 表否定是选A
答
A 因为后边的句子说明他已经去夏威夷度假了.所以肯定不是布朗先生.
must 只能表示肯定推测,否定推测肯定不应该是can't .因为mustn't 表示禁止.
答
表示不可能的时候用can't be 不能用mustn't be。must be用于肯定用法表示一定是can be用于肯定用法表示可能是