Cách sử dụng
A roller can refer to a cylindrical tool with a handle that people use to apply paint or ink onto a surface like walls or paper. It can also refer to a type of machine that is used to flatten or compact things like soil, asphalt or concrete. For example, if someone is renovating their house and wants to paint their walls, they would use a roller to apply the paint. If a construction worker wants to make a smooth road, they would use a roller to flatten the surface. In general, the word 'roller' is used to describe things that roll or flatten surfaces.