19层煤冲击倾向性鉴定结果为：19层煤具有（）倾向性；顶板具有（）倾向性。
参考答案：弱冲击；强烈冲击
The passenger was very impolite to the conductor, ____ , of course , made things even worse.
A．who
B．whom
C．which
D．what
进行轴流风机单项连锁试验时，应具备哪些条件？
