有一读者问： in front of 表示位置， before 也可以表示位置，请问二者有什么区别？
如单从意义上看，二者皆表“在……之前”，好像无甚区别。 实际上，在许多场合中，二者也确是可以互换的，如：
(1)Mary was sitting in front of the mirror. （或用 before）
(2)He was sitting before the door. （或用 in front of）
(3)He clasped his hands before him. （或用 in front of）
(4)He strode slowly across the carpet in front of the log fire. （或用 before）
然而，如仔细体会，这两个介词还是各有一些特点的。试先看短语介词 in front of。这个介词在习惯上常用在建筑物的名称之前，如：
(5)There is a patch of grass in front of the building.
(6)The large tree in front of the governor's house was blown down yesterday.
(7)Be in front of the Dennis house at 3 in the morning and I will pick you up.
(8)Soon the taxi pulled up in front of a small bar on a side street.
在表示近距离意谓“紧在……的跟前”（中间无他物相隔）时，也常用 in front of 或 just （right, directly）in front of,如：
(9)The desk is in front of the blackboard.
(10)She shook an indignant finger in front of his eyes.
(11)We couldn't read the notice because several people were standing directly in front of it.
另外，在与 at (to)the rear of, to the right (left)of 等短语介词连用时，则必须用 in front of,如：
(12)The pictures were taken by somebody who had squatted down in front of and to the left of the jeep with wide lens.
(13)She watched to see if any headlights appeared either in front of or at the rear of the car.
在下面一些句子中表示“在……（人）的面前”时，亦须用 in front of:
(14)You shouldn't use such bad language in front of the children.
(15)How many old poems have you read that you dare show off in front of your elders?
现在我们再看介词 before。一般说来，在我们日常用的非正式的语言中多用 in front of, 在正式文体中多用 before。如下面一些句子都比较文气，故皆用 before:
(16)The fire before them wasted away.
(17)For the moment she was before him downcast and wistful.
(18)Suddenly this scene before him seemed to rise like a curtain in a theatre, and then became blank.
在正式庄严的场合中更常用 before,如：
(19)The old woman offered incense before the image of Guan-Yin.
(20)The pay-master sat in a little booth, with a pile of envelops before him, and two policemen standing by.
(21)You should always adopt an attitude of deference before your superiors.
(22)Everybody trembled before him.
在抽象的比喻中也多用 before,如：
(23)A happy future lies before you.
(24)He never bows down before difficulties.
(25)Old remembrance suddenly rose up before Mary.
(26)Life opened out before him.
与其他介词（如 from）连用时，亦应用 before,如：
(27)The lambs' noise increased to a chorus of baas, upon which Oak pulled the milkcan from before the fire and began to teach them how to drink from the spout of a tea-pot.
最后，再请看这样两句话：
(28)Madame Lomotte stopped before a picture...And Soams crossed over to Madame Lomotte, who was still in front of the picture.
这里把 before 和 in front of 都用上了，那么它们又有什么区别呢？其区别似乎在于： was 是静态动词，故其后用 in front of 较好；动词 stopped 后用 before 或 in front o f 皆可，但为了避免与后文的 in front of 重复，所以使用了 before。
