无码高清视频|成人自拍视频|欧美成人午夜无码A片秀色直播|草美女视频网站|美女被操网站在线观看

單項(xiàng)選擇題

Any extinguishing agent used on a Class “C” fire must have which important property? ()

A.Cooling ability
B.Leaves no residue
C.Penetrating power
D.Nonconductivity

微信掃碼免費(fèi)搜題