在please look after my clothes when i am away.中,为什么i am后面加副词a

e动词后面的成份是表语,名词,介词,介词短语,形容词和副词都可以做表语.副词不仅可以修饰动词,也可以充当表语的成份.
例如：I am here.我在这里.here就是地点副词,放在be动词后做表语.
The fire is out.火熄灭了.
The TV is on.电视是开着的.
My boss isn't in the office.He is out.我的老板不在办公室,他出去了.
Time is up.到时间了.
The sun was down.太阳下山了.
The war was over.战争结束了.

不知道我记得新概念里的2册12课 he will be away for two month
教你一点 be away 后面可以跟时间段