列车中相互连挂的车钩中心水平线的高度差，不得超过（）。
A.50mm
B.75mm
C.90mm
D.120mm
参考答案：B
As the busiest woman in Norton, she made her duty to look after all the other people's affairs in that town. [ ]
A. this
B. that
C. one
D. it
说出硫（S）、氯（Cl）、油对Cat的危害？
