the boys in front of me like fighting each other为什么不是the boys are in front of me like fighting each other一个来自七班的男孩 a boy from class seven为什么不是 a boy is from class seven

the boys in front of me like fighting each other为什么不是the boys are in front of me like fighting each other一个来自七班的男孩 a boy from class seven为什么不是 a boy is from class seven
the boys in front of me like fighting each other
为什么不是the boys are in front of me like fighting each other
一个来自七班的男孩 a boy from class seven为什么不是 a boy is from class seven

the boys in front of me like fighting each other为什么不是the boys are in front of me like fighting each other一个来自七班的男孩 a boy from class seven为什么不是 a boy is from class seven
为什么不是the boys are in front of me like fighting each other
原句换成两句你就知道了:
the boys like fighting each other
the boys are in front of me .
两个句子合成一个.
不能有两个动词啊.
一个就变成短语了.
in front of me 在我前面的,作定语.
a boy from class seven来自七班的.短语
A boy is from class seven
(这里)有一个七班的男孩.
这是句子.有动词了.

the boys in front of me：我前面的男生们
the boys are in front of me ：是我前面的男生们
a boy is from class seven 一个来自是七班的男孩
are 指代the boys，再次出现就重复了，语法错误。
is用法同上

后面的是定语。
你加进去的be动词变成画蛇添足。