问题
选择题
The workers ___ busily when the boss came to look for something she ___ in the office.
A．had worked; had left
B．were working; had left
C．working; had left
D．had worked; left
答案
答案：B
从句when the boss… 给出了内容是句子的重心, 主句用了过去进行时交代背景,因为从句和内容重要,这里的when译成 “”这时”.