镜面磨削是以砂轮微刃的摩擦抛光为主。
参考答案：对
The American team will arrive in Paris to play a friendly match with a team that _____ French and German selected players.
A．consists of
B．is formed of
C．is consisted of
D．is made of
与Q235号钢相比，Q255号钢（）。
A.δ大，σS小
B.δ大，σS大
C.δ小，σS小
D.δ小，σS大
