a major cause

主要原因

The major challenge of this century is to find ways to meet the needs of a growing population.

本世纪主要的挑战是寻求能满足日益增长的人口的需求的途径。

There is a major problem with parking in many cities.

在许多城市停车都是个大问题。

the major subjects

主修课程

I think I should change my major to art history.

我想把专业改成艺术史。

Are most of you English majors?

你们大多数是英语专业的学生吗？

He inspires me to major in English in college, to be a bridge between China and the world.

他鼓励我在大学主修英语，在中国和世界之间起沟通作用。