机车速度变化影响着粘着系数，机车速度增高，粘着系数（）
参考答案：下降
—Why don't you want to live in a big city?
—Because the traffic there is much than that in a small town. [ ]
A. bad
B. worse
C. worst
D. badly
半地下油罐的最高液面比邻近自然地面低（）m以上。
A、0.2
B、0.4
C、0.6
D、0.8
