大哥哥 姐姐 帮下忙了
问题描述：
大哥哥 姐姐 帮下忙了
1.（ ）-Is Jack on duty today?
-lt________be him.lt's his turn tomorrow
A mustn't B won't C can't D needn't
答
C
注：can't 不可能,表“推测,判断”
mustn't 一定不要,不许,表“命令,禁止”.