Be careful when you go the street because the trafficis very busy at the moment.A. across

问题补充：

Be careful when you go the street because the traffic

is very busy at the moment.

A. across

B. behind

C. between

D. over

答案：

(答案→)A. across

B. behind

C. between

D. over

解析：考察介词。across表示从事物的表面通过。Behind在后面；between在中间；over在上面，超过。句意；因为此刻交通很繁忙，但你横穿马路时，加小心。结合语境可知选A。