工件表面磨削后产生深褐色痕迹，是表明工件（）。
A.轻微烧伤
B.严重烧伤
C.没有烧伤
D.被氧化
参考答案：B
The two brothers _____ every day and there was no love left between them.
A．quarreled
B．hated
C．loved
D．worked
There are many children _____ games in the park. [ ]
A. to play
B. played
C. playing
D. play
