金刚石钻头的外径要小于起出的牙轮钻头外径()。
A.1.0~1.5mm
B.1.5~2.0mm
C.2~3mm
D.3~4mm
参考答案:B
Speaker A: I need to make a hotel reservation for my father. Speaker B:______
A.Why does your father want to stay in a hotel
B.Is your father going abroad
C.But do you know how to make a reservation
D.How about calling the travel agency
河南大学现有()个学院(部),()个本科专业。