I use a clock to wake me up because at six o'clock each morning the train comes by my hous

问题补充：

I use a clock to wake me up because at six oclock each morning the train comes by my house.

A. couldn

B. mustn

C. shouldn

D. needn

答案：

A. couldn

B. mustn

C. shouldn

(答案→)D. needn

解析：此处考查情态动词，needn’t+动词原形表示：没有必要做某事。句意：我没有必要用闹钟唤醒我，因为每天早上6点火车都经过我的房子。

【考点定位】考查情态动词的用法。