Thebookwasnotveryinteresting,butbetweenitspagestherewassomethingveryinterestingindeed.itspagestherewassomethingveryinterestingindeed.的引导词是,为什么可以省略,不是仅仅只有that可以省略吗

Question

The book was not very interesting ,but between its pages there was
something very interesting indeed.
its pages there was something very interesting indeed.的引导词是,
为什么可以省略,不是仅仅只有that 可以省略吗

Answer 1

its pages is that there was something very interesting indeed
引导词在从句中做主语时不能省略,做宾语时可以省略.