She is no longer the girl she was before she went to the cou

她不再是去乡下之前的那个女孩儿了。She主语,is系动词,no longer不再,是not的进一步否定形式,the girl表语,与系动词is一起构成系表结构做谓语。she was是由that 或who引导的定语从句（在些省略引导词that或who),修饰the girl,before she went to the countryside是定语从句的时间状语从句。