问题
选择题
(2012·全国卷Ⅰ)I ________ use a clock to wake me up because at six o'clock each morning the train comes by my house.
A．couldn't
B．mustn't
C．shouldn't
D．needn't
答案
答案：D
选D 考查情态动词。句意：我不需要用闹钟叫自己起床，因为每天早上六点都会有一列火车经过我家门口。应选“不需要”，即needn't。