是behind 还是 at the back of?

behind或at back of

behind   in front of   
at the back of    in the front of

behind反义词是in front of指物体外面
at the back of 反义词是in the front of 指物体里面

“behind反义词是in front of指物体外面
at the back of 反义词是in the front of 指物体里面”  同意   很到位