While _____ in the room, we were all very excited.
A.waited
B.waiting
C.to wait
D.wait
答案:B
斜拉桥中设置辅助墩起什么作用?
水尺附近的水流方向分为()、逆流或回流、停滞三种情况。
A.南北流
B.东西流
C.涡流
D.顺流