压缩机充加润滑油的目的是为了减少压缩机的（）。
A.机械磨损
B.摩擦噪声
C.摩擦功
D.摩擦阻力
参考答案：A, C
it looks, we should be.
A. The easy, the careful
B. The easier, the carefuler
C The easiest, the most careful
D. The easier, the more careful
Progressive， proportional， and regressive taxes 累进税、比例税和累退税
