major既可以作动词，也可以作名词，还可以作形容词。

（1）作动词

major in: to study something as your main subject at a university or college主修

He majored in History at Stanford.

他在斯坦福主修历史。

major on: to pay particular attention to one subject, issue, etc.专门研究（课题、问题等）

Many students find themselves Wasting one major on their college applications, but switching to another after taking college classes.

许多学生发现自己在大学申请时选了一个专业，而上过大学课程后就换成了另一个专业。

（2）作名词

①an officer of fairly high rank in the army or the US air force少校

He is a major in the US army.

他是美国陆军少校。

②the main subject or a course of a student at college or university主修课程，专业课

Her major is French.

她的专业课是法语。

③a student studying a particular subject ss the main part of their course主修学生，主修生

She is a French major.

她是法语专业的学生。

（3）major还可作形容词，此处不再赘述。