如果钻孔后还需要加工或攻螺纹，则钻孔时要用直径较小的钻头，一般要比需要的孔径或螺栓小0.20mm或更小些。此种说法（）。
A.对
B.不对
参考答案：A
一束光与水平面夹角为30°，则其反射角等于______，折射角范围是______．
用恰当的词语填空．完成对话。每空一词。(每小题1分．共5分)
W: Excuse me, is there a bookstore around here?
M: Yes. There is 小题1: on Zhongshan Road. It's between the parking lot and the supermarket.
W: How 小题2: is it from here?
M: About thirty minutes' walk. You can 小题3: the No. 14 bus there.
W: Thank you. By the way,小题4: the bus stop?
M: It's at the end of this street. You can't 小题5: it.
W: Thanks for your help.
M: You're welcome.
