—I am going to America.—how longyouthere?A. are; stayedB. are; stayingC. have; stayedD. di

问题补充：

—I am going to America.

—how longyouthere?

A. are; stayed

B. are; staying

C. have; stayed

D. did; stay

答案：

A. are; stayed

(答案→)B. are; staying

C. have; stayed

D. did; stay

解析：本题考查时态。此处用进行时态表将来。