what does milk mean怎么回答

a white nutritious liquid secreted by mammals and used as food by human beings。英语学科的介绍：英语已经发展了1400多年。英语的最早形式是由盎格鲁-撒克逊人移民于5世纪带到英国的一组西日耳曼语支（Ingvaeonic）方言，被统称为古英语。

1、produced by mammary glands of female mammals for feeding their young.

2、a white nutritious liquid secreted by mammals and used as food by human beings.

3、any of several nutritive milklike liquids.