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