问题

Could you tell me __________—Certainly. In half an hour.
A:how long will the train to Beijing leave
B:when the train to Beijing would leave
C:How soon the train to Beijing left
D:How soon the train to Beijing will leave;
B:when the train to Beijing would leave
C:How soon the train to Beijing left
D:How soon the train to Beijing will leave;
正确答案是: