题干
—What do you think we can do for our aged parents?
—You ________ do anything except to be with them and be yourself.
—You ________ do anything except to be with them and be yourself.
A：don’t have to
B：oughtn’t to
C：mustn’t
D：can’t
答案(点此获取答案解析）
A
在
内单调递增，
，则
是
条件.（ ）