Cách sử dụng
A backpack is a bag that you wear on your back, usually made of fabric or leather. It is used to carry things like books, clothes, or food when you go to school or hike in the mountains. You can also use it to carry your belongings when you travel. A backpack can be big or small depending on how much stuff you need to carry. It is a convenient way to keep your hands free while carrying your things.