不属于煤气的三大特性的是（）。
A.易燃
B.易爆
C.易腐蚀管道
D.易中毒
参考答案：C
标有“220V-1000W”字样的电火锅，接在家庭电路中正常工作2h，消耗的电能是_________KW?h。
All the students in this school are required to________at least two lectures on how to study every month.[ ]
A. attend
B. take part in
C. join in
D. go in for
