Which sentences are written correctly?

Many people learned how to drive when they turned 16 years old before they can buy vehicles.


Some people use phones that are plugged into their walls, but most people carry cell phones.


If you live by yourself, a cat was an excellent pet for you to own.



People who bought food at grocery stores have more money than people who went out to eat.


Kids who take piano lessons sometimes become rock stars.


Public libraries store books and offer the free use of computers