淬火处理是将含碳量0.4%的钢铁加热至850℃后，（）的一种热处理过程。
A、以空气来冷却
B、急速冷却
C、慢慢冷却
D、以水来冷却
参考答案：B
—You are leaving your school．How do you like it?
—Very much, of course, I this school since I moved here
A．came to
B．have gone to
C．have been to
D．have been at
