serve in, serve on
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, serve one's time
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。
serve as, act as
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。
下面三句意思相同:
She served us a good dinner.
She served a good dinner to us.
She served us with a good dinner.
她给我们准备了美餐。
下面两句意思不同:
She served in a bar.
她在酒吧当招待。
She served at a bar.
她在吧台上当招待。
