May I take this book out of the reading room?No,you _____.You must obey the rules.

问题描述:

May I take this book out of the reading room?No,you _____.You must obey the rules.
A can"t B may not C needn"t D aren"t

A can't 习惯用语,而且和后面的must形成语气呼应,彼此协调.