1、作副词

①大约,左右.如:There are about 30 students on the playground.操场上大约有30个学生.

②将要,将近.如:I’m about ready.我快准备好了.

③到处,各处.如:The children are running about.孩子们到处乱跑.(表示动向)People are sitting about on the grass.人们在草地的各处坐着.(强调位置)

2、作介词

①在……到处;在……各处.如:He is walking about the town.他在城镇到处走.

②关于;对于;有关.如:I am going to read a book about that big city.我要读一本关于那个大城市的书.

3、固定搭配

①be about to do sth.如:We are about to start.我们即将动身.

②what/how about...……怎么样?(用于询问信息或征求意见)如:How about going to Canada for our holidays?咱们去加拿大度假,好吗?