—Could you tell me __________? 

        —Certainly. In half an hour. 

A. when will the train to Beijing leave

B. when the train to Beijing would leave

C. when the train to Beijing left

D. when the train to Beijing leaves

—Could you tell me __________?  

—Certainly. In half an hour.

1. A.
   when will the train to Beijing leave
2. B.
   when the train to Beijing would leave
3. C.
   when the train to Beijing left
4. D.
   when the train to Beijing leaves

—Could you tell me ________?   —Certainly. In half an hour.

A. when will the train to Beijing leave   B. when would the train to Beijing leave

C. when the train to Beijing leaves      D. When the train to Beijing left