斜井轨道每隔（）设一处轨道防滑器。
参考答案：50米
--- The couple _______ after 10 years’ marriage.
--- What a pity. Their child may suffer a lot from this.
A．broke out
B．broke down
C．broke up
D．broke into
粒子对电磁波作用的两种基本形式是（）。
A.散射
B.反射
C.折射
D.吸收
