Joy as a language teacher in China for two years before she went back to London.
A. had worked
B. was working
C. worked
D. has worked
网友回答
(答案→)A. had worked
B. was working
C. worked
D. has worked
解析：句意：乔伊去伦敦之前，已经在中国做了两年的语言老师了。作为语言老师这个动作发生在went back回去之前，所以用过去完成时，故选A