最有趣的……,后面跟名词（单数,因为是【最】了）,比如thing
简短地写了the most interesting thing
The most interesting thing must be books .We can know many thing from the book.Like history,math,science,art…We can study all the interesting things from the books.If you have some questions,we can look up books.We know a lots of interesting things around us,far away us,and outside the earth.Books make us feel interested,so they are most interesting things.