before 一般指 时间的概念 -- 对应 after
in front of 指 X在Y的前面 X与Y是两个相对独立的物体 -- 对应 behind
比如TOM sit in front of me.TOM坐在我的前面
in the front of 指X在Y的前部 这里 X是Y的一部分 或者在Y 内部
例如 I sit in the front of the classroom.我坐在教室的前部
----------------
behind 主要是指空间或事物的后面.
after 主要是指时间或事物的后面
I stand behind you.
A street behind the station.
After dinner.
day after day.
I'll come after next Monday.
它们还有别的意思,尤其是after.
The payment was behind schedule.
She came in after me.
Close the door after you when going out.