用恒线速度控制加工端面、锥度、圆弧时，（）坐标不断变化，当刀

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问题单项选择题

用恒线速度控制加工端面、锥度、圆弧时，（）坐标不断变化，当刀具逐渐移近工件旋转中心时，主轴转速会越来越高，工件可能从卡盘中飞出。为防止事故发生，必须限定主轴最高转速。

A.X

B.Z

C.X和Z

D.Y

答案

参考答案：A

计算题

补全对话，情景问答

情景交际,每空一词。

A: Hi, Li Yan! Have you ever been l the local library before?

B: You mean the one near the Dragon Tower?

A: That's the one.

B: I go to the English Corner in the library every Saturday. A lot of' English lovers practice spoken English

together. Why 2 you join us?

A: Sounds great! Could you tell me how to get there?

B: The No.7 bus will take you right there.

A: How _3 is it?

B: It's about twenty minutes' ride.

A: _4 _ is the nearest bus stop?

B: Walk along the street and take the first turning on the left. It's opposite the post office. You can't 5 it.

A: Thanks a lot.

B : You're welcome.