I think the hardest thing is when you hate it and don't want to do it, no matter what; When you like it and are interested in it, you will find it easy to spend even two hours.

I usually think by myself, and then find a book to read, and basically don't ask my classmates. ......

Of course not. Simple topics also have their meanings. People with good grades should think that this is one of the ways to build confidence for those with poor grades and should not be underestimated. ......