退火处理是材料加热后，自然冷却的一种热处理过程。
参考答案：对
I knew that _____ would ever discourage him, he would never give up wanting to be a director. [ ]
A. something
B. anything
C. everything
D. nothing
膛线反映在射击弹头上成左上往右下倾斜线痕迹的为（）旋。
A.右
B.左
C.螺旋线
D.抛物线
