By the time he arrives in Beijing we here for two days.A. will have stayedB. will be sta

问题补充：

By the time he arrives in Beijing, we here for two days.

A. will have stayed

B. will be staying

C. have been staying

D. have stayed

答案：

(答案→)A. will have stayed

B. will be staying

C. have been staying

D. have stayed

解析：考查时态：句意：在他到北京的时候为止，我们已经呆在这儿两天了。说明我们在这儿待两天是在他到这儿之前，用过去完成时。还有介词by，是和相应的完成式连用的，by接过去时间，用过去完成时，by接将来时间，用将来完成时。选A。