圆形断面钢材，截面上出现两个相互垂直、直径不等的现象，这两个直径的差值叫（）。
A、公差
B、不圆度
C、差值
参考答案：B
三角形具有______性，每个三角形都有______条高，三角形的内角都是______，三角形任意两边之和______第三边．
A: My telephone doesn’t seem to be working. And I have lots of calls that I have to return this evening.B：().
A. What a terrible day you have!
B. Do you find someone to take care it for you
C. My telephone works very well.
D. Feel free to use mine if you want.
