高炉煤气有何特点？
参考答案：
①高炉煤气是无色无味无臭的气体。
②因CO含量很高而毒性大。
How come you stepped into the lab with your shoes on? You’re ________to take them off before you enter it. I told you so.
A．suggested
B．supposed
C．forbidden
D．permitted
下列属于放电线圈必填项的有（）
A.相别
B.相数
C.额定变比
