The width of a proton is a thousandth of the width of an atom, the width of an atom is a millionth of the width of a hair, and the width of a hair is a thousandth of one millimeter.

• 一个质子宽度是原子宽度的千分之一，原子宽度是一根头发宽度的百万分之一，一根头发宽度是一毫米的一千分之一。