题目

-Hi! Tom, can you tell me something about your tomorrow’s school trip? -Sure. We decided to ____early in order to avoid the traffic.  A. set up   B. set off    C. set back    D. set on 答案：B站台上停着甲乙两列火车，当甲车上的人发现乙车动了，下列说法中最准确的是（ ）A．甲车开始开动B．甲乙两车开始向相反的方向开动C．乙车开始开动D．上述情况都有可能