As they are expected to be hungry after their long journey,food is laid out for them.这是新概念二第96课中的一句话,请问一下这里的as可不可以用for代替,它们之间又有什么区别?

问题描述:

As they are expected to be hungry after their long journey,food is laid out for them.
这是新概念二第96课中的一句话,请问一下这里的as可不可以用for代替,它们之间又有什么区别?