接单根操作时,小鼠洞对螺纹,待钻杆上紧后,合低速;方钻杆提升时改用高速,单根起出鼠洞3/4摘高速。
参考答案:对
根据对话内容,填上恰当的句子补全下列对话。
(A=Salesgirl B=Mrs Green)
A: Good afternoon! Can I help you?
B: Yes, please. I'm looking for a mobile phone.
A: We have many popular kinds, like Motorola, Nokia and so on.
B: I prefer (更喜欢) the things made in China. ____ 1____ ?
A: Yes, TCL is also popular. What about this one? 2 _ __ .
B: Well, I don't want the newest. I'd like a practical (实用的) one.
A: This one looks nice and works well.
B: _____3 ?
A: 1,350 yuan.
B: ______4_____ _ . But I'll take it.
仅能承受轴向载荷的轴承为()。
A.向心轴承
B.推力轴承
C.向心推力轴承
D.推力向心轴承