这些前置词（短语）均含有“在……前”之意。
before : 指空间位置或时间的“在……前”。表时间时，反义词为after；指空间位置时，其反义词是behind。
- You should always wash your hands before meals.
饭前应该洗手。 - Before leaving he said goodbye to each of them.
走前他和每个人都告了别。 - She's always up before dawn.
她总是黎明前就起床了。 - Before he could reach the door, she quickly closed it.
他还没走到门前她就迅速关上了门。 - Before we make a decision, does anyone want to say anything else?
趁我们还未作决定，还有人想说什么吗？ - She had to give the doorman a tip before he would help her with her suitcases (= he would not do it until she had given him a tip).
她得给看门人小费，好让他帮她提箱子。
in front of : 指在某地方之外的前面，即不在其中，多与静态动词连用，通常可与before通用。
- She started talking to the man in front of her.
她开始跟前面的那个男人攀谈起来。 - I stood for a few moments in front of the nearest shop window.
我在最近的一家商店的橱窗前站了一会儿。 - They put a screen in front of me so I couldn't see what was going on.
他们在我面前竖了一面屏风，所以我看不到发生了什么事情。 - We dried our clothes in front of the fire.
我们在火前烘干了衣服。
in the front of : 指在某地方之内的前面，即在其中的前部分。
- The driver sits in the front of the bus.
驾驶员坐在公共汽车的前端。 - Put the shortest flowers in the front (of the bunch).
把最短的花放在花束的靠前位置。 - There is a table of contents in the front of a dictionary.
词典的开头有目录表。
