at the back of和in the back有区别吗,in back of呢?再问一下反义词组

1.at the back of 在）.（内部的）后面.
比如在房间,房间内的后部
反义词：at the front of ...
2.in the back of 在.背后.（要陷在里面）.这个很少用的.
You really need eyes in the back of your head.
3.
in the back of是指在空间的后面,比如 the blackboard is in the back of the classroom.教室后墙上有块黑板.