磨削导热性差的材料或容易发热变形的工件时，砂轮的粒度应细些。。
参考答案：错
在下列物质中，属于化合物的是 [ ]
A.液氧
B.生铁
C.石油
D.干冰
---Excuse me, could you tell me _______________________?
--- It will leave at 3:00 p.m.
A．when will the plane leave for Shanghai
B．when the plane will leave for Shanghai
C．how will you go to Shanghai
D．how you will go to Shanghai
