道口信号的白灯稳定亮时，表示（）。
A.道口开通，准许车辆行人通过
B.火车接近道口，禁止车辆行人通过
C.道口信号无效
参考答案：A
—Could you tell me _________? —Sure. It’s near the bank on the other side of the street.
A．when was the post office built
B．when the post office was built
C．where is the post office
D．where the post office is
投标文件由（）本正本和（）本副本组成。
A.一；二
B.二；四
C.二；二
D.一；四
