is something that

Why do you study English?

What made you decide to study English?

What is something that you study English?

...is something that...

間接的に言う、言い換えることができる

That is...（とっさに言葉がでてこない）something that has a lot of history.

There is...(いきなり伝えたいことがあると直接的に言いずらい）something that I really want to tell you.