办公室中的安全隐患有（）
A.办公室摆放档案柜
B.地面上有电话线拖曳
C.站在旋转椅上去东西
D.消防栓放置在文件柜后
参考答案：B, C, D
______clearly in class, Mr. Smith raised his top voice to ask his students to stop chatting.
A．Found not heard
B．Found not hearing
C．Finding not heard
D．Finding not hearing
抽象分析法。
