接触网作业车的同一轴上车轮，直径差不得大于（）mm。
参考答案：1
So hard was the woman’s life, but to her _____ , her only son was admitted to a top university last year.
A．surprise
B．relief
C．astonishment
D．disappointment
金属脚手架与±800kV及以下带电架空线路沿垂直方向的最小安全距离为（）m。
A.10
B.11
C.12
D.13
