Question

I think that that that that that student wrote on the blackboard was wrong.

I think that that that that that student wrote on the blackboard was wrong.我认为那个学生写在黑板上
第四个that引导的是定语从句，还是同位语从句呀？（貌似第四个that在从句中不充当成分呀）

Answer 1

I think that-1 that-2 that-3 that-4 that-5 student wrote on the blackboard was wrong.
为了看的方便，把5个that都依次编上号，下面进行拆解：
1. I think (that-1) that-2 that-3 was wrong （that-1，连接词，后接宾语从句，自身无意义，可省略；that-2，指示代词，“那个”；that-3，指的是写在黑板上的单词“that”）
2. that-2 that-3 that-4 that-5 students wrote on the blackboard was wrong （that-4，连接代词，引导定语从句，代替写在黑板上的单词'that'做定语从句（that student wrote on the blackboard）中wrote的宾语）
3. that-5 student wrote on the blackboard （that-5，指示代词，“那个”学生）

全句意为：我认为那个学生在黑板上写的那个单词（that）是错误的。
这个句子充满娱乐精神，但没有用武之地，于交流无益；如果想表达相同语意，可以改写为：
I think the that which the student wrote on the blackboard was wrong.
限定词the 代替 指示代词 that
连接代词which 代替 连接代词 that
宾语从句连接词that 可省略

Answer 2

这都行 。。。

Answer 3

怎么看好像都多写了一个耶？