在……前面： in front of…；in advance of；in the face of 在……的前面： at the head of；in front of …, 面对，在……前面： in front of 在……后面： in back of；,behind；at the back of at the back of（=behind）； 太阳在云层后面消失了。

The sun disappeared behind the cloud. 您是排在这位先生后面的。请在他后面等候。 You are next to this gentleman. Please wait behind him. 我知道那个人。他总是跟在漂亮女孩的后面。 I know that man. He is always after pretty girls.