Question

【题目】_______ his mother was cooking in the kitchen, the boy fell asleep in the chair.

A. Since B. While C. Because D. Once

Answer 1

【答案】B

【解析】句意：当他的妈妈在厨房做饭的时候，这个男孩在椅子上睡着了。A. Since自从； B. While 当……时候；C. Because因为；D. Once一旦。While引导的句子经常用进行时，表示在从句的动作进行的过程中，发生了主句的动作。故选B。