proportional: may apply to several closely related things that change without altering their relations: medical fees are ~ to one's income.  



proportionate: applies to one thing that bears a reciprocal relationship to another: a punishment not at all ~ to the offence.  


commensurate: stresses an equality between things different from but in some way dependent on each other: the salary will be ~ with experience.


commensurable: more strongly implies a common scale by which two quite different things can be shown to be significantly equal or proportionate: equal pay for jobs that are ~ in worth.

proportional: 成固定的比例，proportionate: 强调相互(reciprocal)协调相称介词用to，commensurate以...作为根据介词用with，commensurable: 这种比例关系可以测量评定(by a scale)


记忆方法： 1）中间的PC都以ate结尾，意思接近。以p开头的介词用to，另一个with。


           2） PPCC，联想个人电脑PC，个人电脑和手机的比例固定

           3）比例的意思是事物间存在适当的比值mean in due ration to something else.