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

（）, remedies must be taken to stop it as early as possible.

A.Any surge occurs
B.Any surge occurred
C.Should any surge occur
D.Should any surge occurring

你可能感興趣的試題

單項(xiàng)選擇題

（）, the motion would continue indefinitely once it had started.

A.Were there loss of energy by friction
B.Since there be loss of energy by friction
C.Were there no loss of energy by friction
D.Should be no loss of energy by friction

單項(xiàng)選擇題

（） the bodies are, （） the friction will be.

A.The smoother；the greater
B.Smoother；less
C.The rougher；the greater
D.rougher；greater