By the time you arrive in Liverpool, we in France for two weeks.
A. shall stay
B. have stayed
C. will have stayed
D. have been staying
网友回答
A. shall stay
B. have stayed
(答案→)C. will have stayed
D. have been staying
解析：考察时态。句意：当你到达利物浦时，我们已经在法国两个星期了。可知下文描述的是在将来某个时间点前完成的动作，故用将来完成时态，选C。