刃磨（）镗刀时，应经常将发热的镗刀片放在水中及时冷却，以免镗刀片刀升温过高而造成退火软化。
A.高速钢
B.硬质合金
C.立方氮化硼
D.陶瓷
参考答案：A
Most species of this plant thrive in ordinary well-drained garden soil and they are best planted 8 cm deep and 5 cm apart.
A．develop well
B．grow taller
C．mature
D．bear fruit
分项、分部工程是如何划分的？
