加工一个窄长平面，精度为ＩＴ９，Ｒａ≤６.３um，应选用（）。
参考答案：刨削
David is as _____ as Jack. [ ]
A. care
B. careful
C. more careful
D. the most careful
顿首：古代一种拜礼，为“（）”之一，俗称叩头。
