—I am going to America.—how long you there?A. are; stayedB. are; stayingC. have; stayedD.

问题补充：

—I am going to America.

—how long you there?

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：考查时态。用现在进行时代替一般将来时，表示按照计划安排要发生的事情。句意：—我要去美国、—你计划在那里待多久？故B正确。