There is an interval of ten minutes between the two classes，________we can have a rest.
A：when
B：where
C：what
D：which
在现代交通中，高速列车已成为现实，为了不影响高速列车的运行，有人设想：若能使高速列车进出站时既不停车又能上下乘客，岂不更好？你能进行这样的设计吗？若能设计，请说明怎样设计。____。
主导雅尔塔体系的两个大国为（ ）
Mary keeps talking about the party. She had a very good time,_______?
