A.+→
B.→+
C.+→
D.→+
答案:D
The father as well as the three children ______ every Sunday afternoon in winter.
A.is going
B.go
C.goes
D.are going
数控镗床的加工顺序是()。
A.铣大平面(粗、精铣分开)
B.粗镗孔、半精镗孔
C.立铣刀加工
D.中心钻预钻中心孔
E.钻孔、攻螺纹
F.孔、面精加工