Question

When the old man ______ to walk back to his house, the sun ______ itself behind the mountain．

1. A.
   started; had already hidden
2. B.
   had started; had already hidden
3. C.
   had started; was hiding
4. D.
   was starting; hid

Answer 1

A
思路解析：本题考查的是动词的一般过去时和动词的过去完成时的用法。一般过去时表示过去某个时刻发生的动作或情况，过去完成时表示某时之前已发生的动作或情况(简单地说，即“过去的过去”)。题中when引导的时间状语从句，描述的是过去的动作，主句发生的动作在从句发生的动作之前，所以从句的时态用一般过去时，主句用过去完成时。故选A项。绿色通道：在包含有when, as soon as, before, after, until等连词的复合句中，如果主句谓语和从句谓语表示的动作是在不同的时间发生的，那么先发生的动作需用过去完成时。如：He had finished his homework before his parents came back．