We have PE lessons ______ every Tuesday and Friday. [ ]
A. /
B. on
C. in
D. at
答案:A
以下属于Ⅱ类爆炸危险物质的是( )
A.矿井甲烷 B.爆炸性蒸气C.爆炸性粉尘 D.爆炸性飞絮
政府权力的行使包括决策、执行、监督等环节。()