Question

这句话的语法结构怎么分析，谢谢！

Over the next four years, this student, who considered herself intelligent, found herself in classed and social events in which people of other races performed as well as or more competently than she did.

Answer 1

主句：this student found herself in classed and social events.
Over the next four years是时间状语。
who considered herself intelligent是非限制性定语从句，修饰this student。
in which people of other races performed as well as or more competently than she did又是一个定语从句，修饰events。

in which people of other races performed as well as or more competently than she did包含了两个比较状语从句，相当于：
in which people of other races performed as well as she did + in which people of other races performed more competently than she did。

句意：在接下来的这四年里，这个自认为很聪明的学生发现自己处在等级森严的社会事件中，在这里，来自别的种族的人比她还要更有竞争力，至少不比她差。
（in classed and social events译为“处在等级森严的社会事件中”不一定贴切。以上译文仅供参考。）

Answer 2

如果不是你问的话，我还觉得这是个病句呢。呵呵~~~

Over the next four years 很明显，时间状语
this student,主语
who considered herself intelligent 修饰主语的定语从句
found herself in classed and social events in which people of other races performed as well as or more competently than she did. 是问题所在。也是难点所在。其中，in which从句

即in which people of other races performed as well as or more competently than she did. 很容易理解，就是修饰social events 社交活动或者社交场合，其他人种的人表现得跟她一样好甚至比她更好。

问题出在两个in。个人觉得，这句很奇怪。我保留意见。意思是很明白的了。主句意思就是
this student found herself +(宾补从句) 这个学生发现自己（不是想像的那样睿智）