—Oh, Mum, just a few minutes．
—Hurry up, Harry, or by the time you pack your belongings, the flight .
A. has left
B. will have left
C. had left
D. will be leaving
网友回答
A. has left
(答案→)B. will have left
C. had left
D. will be leaving
解析：By到…时为止；经常和表示动作的动词的完成时连用。本句中by the time后面的时间状语从句you pack your belongings使用了一般现在时代替将来时，后面的主句要使用将来完成时，表示到将来的某个时间将要完成的事情。句义：—妈妈，再等几分钟。—快点！到你收拾好物品的时候，我们的航班都已经起飞了。故B正确。