问题补充:
There must be many people for their trains at the train station because of the golden week holiday.
Aare waiting
B. waited
C. to wait
D. waiting
答案:
A. are waiting
B. waited
C. to wait
(答案→)D. waiting
解析:句意:因为黄金周,在车站一定有很多人在等待他们的火车。本题考查There must be sb doing sth.某地一定有人在做某事。根据句型,故选D。