请问before和in front of,in the front of有什么区别

You can't buy them in the shop before eight o'clock.八点之前你在商店里买不到那些东西.
How many students stand in front of the class? 有多少学生站在同学们面前.
[辨析] before与 in front of都有“在.之前”的意思,当表示“在某种位置前”时,两者可以通用.例如：
She sits before/in front of me in the classroom.在教室里他坐在我的前面.
in the front of是只在前面的部分
They are standing in front of/before the blackboard.他们正站在黑板的前面.
当表示“在某建筑物前面”时,宜用in front of.例如：
The car stopped in front the cinema. 汽车停在电影院的前面.
当表示“在某段时间”,“某一事件”之前时,用before,不用in front of.例如：
Before liberation he lived a poor life.*他过着贫穷的生活.
Please come to see me before Sunday.请在星期六以前来看我.