-- Did you visit your grandparents yesterday?
--Yes, and when I got there, they in the fields .
A. worked
B. have worked
C. were working
D. had worked
网友回答
A. worked
B. have worked
(答案→)C. were working
D. had worked
解析：句意：--昨天你去看祖父母了吗？--是的，当我到达那里的时候，他们正在田里干活。时间状语是when I got there,说明是在过去某个时间正在做…，符合过去进行时的用法，选C。