节理的存在对煤矿生产有哪些影响（）。
A.只影响开采效率
B.只影响顶板管理方法
C.只影响工作面布置
D.以上说法均不对
参考答案：D
Some of the engines were not suitable for the work they were ________ for.
A．intended
B．to intend
C．intending
D．being intended
调车冲突，列一般（）事故。
A.A类
B.B类
C.C类
D.D类
