It's nothing. What should I study?

It's okay. You can learn something useful.

Doing nothing means that you have a lot of free time. And you can say that you don't have to do anything, and you don't have to worry about the daily necessities at home. You don't need to worry about the rent, water and electricity at home, and you don't need to worry about the expenses at home. I guess you don't have to worry about three meals a day. Your parents will help you cook. You just need to eat and dress. There is no pressure in life, work and study. That's why I feel that I have nothing to do.

Nothing to do, just something to do. You can learn useful things, and you can also learn useful things in your future work. For example, you can learn some statistics and economics. You can also study some professions you like, such as accounting. Or you can learn some psychology.

Personally, I suggest you learn some psychology and professional knowledge. Psychology is more important to get along with people in the future work. Professional knowledge depends on what position you want to engage in in the future, and write the professional knowledge of the position if you want to engage in any position.

Or you can learn to drive and get a driver's license. Now the driver is a skill that everyone must master, and driving will be much more convenient. It will be useful to take a driver's license test first when you are free.

In short, you can learn everything, mainly depending on what you need and like. You can know what you need and what you like.