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．was starting; hid
C．had started; had already hidden
D．had started; was hiding
答案
答案：A
题目分析： 考察时态。句意：当老人开始走回自己的房子的时候，太阳已经躲在大山后面了。根据句意可知太阳落山是先发生的事情，然后老人才回家。要注意动词的先后关系，故A正确。