车辆的车轮轮缘顶部高于轨面时（因作业需要的除外）称（）。
A.脱落
B.脱轨
C.颠覆
D.复轨
参考答案：B
— Would you like some bread? — ________________. I’m hungry.
A．Yes, please
B．No, thanks
C．Yes, I would
D．No, I won’t.
地壳里含量最多的金属元素是 ( )
A．铁
B．氧
C．硅
D．铝
