be made of be made in 有什么区别 in front of inthe front of 有什么区别?

be made of 由.制造而成.如Paper is made of wood.
be made in .制造.如 This watch is made in China.
in front of 在.前面.
in the front of在.前面
如：你坐在教室前面.猫在教室的前面（教室外）.
You are sitting in the front of the classroom.
The cat is in front of the classroom.