一般（）加工可获得尺寸精度等级为IT6-IT5，表面粗糙值为0.8~0.2微米。
A.车削
B.刨削
C.铣削
D.磨削
参考答案：D
My parents _____ eat junk food, because it's bad for our health. [ ]
A. often
B. never
C. sometimes
D. always
哪种民用建筑的采暖散热器必须暗装或加防护罩()
A．办公楼
B．高层住宅
C．学校
D．幼儿园
