By the time you get to Beijing tomorrow I for Shanghai.A. am leavingB. should have leftC

问题补充：

By the time you get to Beijing tomorrow, I for Shanghai.

A. am leaving

B. should have left

C. will leave

D. will have already left

答案：

A. am leaving

B. should have left

C. will leave

(答案→)D. will have already left

解析：考查时态。根据句中时间状语by the time和tomorrow可知用将来完成时，选D。