铣斜面一般常用哪些方法？
参考答案：
把工件转成所需角度铣斜面、把铣刀转成所需角度铣斜面、用角度铣刀铣斜面。
Most Americans would prefer to keep their problems ______ themselves, and solve their problems ______ themselves.
A．to; by
B．by; to
C．for; to
D．in; on
血站对献血者必须免费进行必要的健康检查。（）
