常见电梯按用途分有（）。
A.乘客电梯
B.载货电梯
C.客货梯
D.直流电梯
E.液压电梯
参考答案：A, B, C
. School children must be taught how to deal with dangerous ________.
A．states
B．conditions
C．situations
D．positions
封君封臣
