题目

I want to see him       he arrives. Which of the following is wrong. A. at the moment        B. directly           C. immediately        D. instantly 答案：A 解析: 略 火车站自动扶梯用时间t1可将一个站在扶梯上的人送上去.若自动扶梯不动,人沿梯走上去要t2的时间.若此人沿运动的扶梯走上去,需要时间是_________.