serves

这两个短语都表示“在…任职”。它们的区别是：

serve in用于相对较大的范围,而serve on用于相对较小的单位与机构。

serve time的意思是“蹲过班房”或“吃了官司”; 而serve one's time则作“满期”或“见习期满”解。试比较:

The blackguard has served time for three years.

那坏蛋已坐了三年牢。

Tom has served his time.

汤姆已经转正了。

这两个短语都可表示“充任,担任”。它们的区别是：

serve as多指长期供职; 而act as所指时间则相对较短。试比较:

He serves as manager and interpreter.

他兼任经理和口译。

She will act as my guide tomorrow.

明天她将给我作向导。