可燃性粉尘环境用电气设备分为()种类别。
A、2
B、3
C、4
D、5
参考答案：C
经线呈__________形状，纬线呈__________形状。
Do you like the ________ magazine __________Zhi Yin? [ ]
A. month; calling
B. monthly; called
C. month; called
D. monthly; calls
