The book is very interesting.I have read it there times.（把两个

The book is very interesting.I have read it there times.（把两个句子合并为一句)

The book that I have read three times is very interesting.
再问： 所给句型是The book is _____ interesting _____ I have read it there times.
再答： The book is ___so__ interesting ___that__ I have read it there times.
再问： 为什么啊？
再答： so ... that 引导的结果状语从句啊。原来是两个简单句，合并为一个句子的时候只能成为并列句或者是复杂句，并列句意思说不通，所以只有复杂句，这里通过横线的位置，我们定位成 状语从句。