如果是定语从句，most of后面不接that而是接which，因为of是一个介词。例句：

1.There are a great number of books in the reading-room,most of which are about science books.

阅览室里有大量的书，其中大部分是关于科技方面的书。

most of的后面跟代词宾格

例如

Most of us like to play basketball on the weekend in our school.

Most of them have hamburgers for breakfast.