不是介词，guest，是名词词性，意思是客人，例如：
1、Guests are requested to vacate their rooms by noon on the day of departure.房客务请在离开之日的中午以前腾出房间。
2、At that time my mother took in paying guests.那时候，我妈妈接待房客。
3、Apparently， many guests had felt and seen a variety of things.显然，很多房客感觉到或看到了一些东西。
