In brushing your teeth, drawing, reading and combing your hair, combing your hair is different. Brushing your teeth, drawing and reading are all verbs, which mean different actions or activities respectively. Brushing refers to the act of cleaning teeth with a toothbrush, painting refers to the artistic activity of creating images on a plane with pigments or other media, and reading refers to the act of reading books or other documents. These verbs all express the dynamics of people when they are doing some activity or operation. Comb is a noun, which means a tool for combing hair. Nouns are usually used to express people, things, concepts, etc. ,, and are words that describe things in language. In this phrase, only the comb is a noun, and the other three are verbs.