When the old man ______ to walk back to

问题选择题

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

mountain.

A．started; had already hidden

B．had started ;had already hidden

C．had started; was hiding

D．was starting; hid

答案

答案：A

题目分析：考查时态。句意：当老人开始走回家的时候，太阳已经下山了。说明太阳下山是在老人回家之前。老人回家用过去时，太阳下山用过去完成时。这两句的时态要一致，故A正确。

点评：过去完成时一定要注意时间的起点，它不是的是过去的过去，要找到时间的参照点。