题目

John is the tallest boy in the class, _______ according to himself. A. five feet eight as tall as                B. as tall as five feet eight C. as five feet eight tall as                D. as tall five feet eight as 答案：B 跳伞运动员做低空跳伞表演，当飞机离地面某一高度静止于空中时，运动员离开飞机自由下落，运动一段时间后打开降落伞，打开伞后运动员以5 m/s2的加速度匀减速下降，则在运动员减速下降的任意一秒内(　　) A．这一秒末的速度比前一秒初的速度小 5m/s B．这一秒末的速度是前一秒末的速度的0.2倍 C．这一秒末的速度比前一秒末的速度小5 m/s D．这一秒末的速度比前一秒初的速度小10 m/s