主修市场营销用英语怎么说

主修市场营销用英语可以说是 "major in marketing"。来源是英语中的 "major" 意为主修，"in" 意为在...之中，"marketing" 意为市场营销。

例句：

I majored in marketing in college. (我在大学里主修市场营销。)
She decided to major in marketing because she was interested in the field. (她决定主修市场营销，因为她对这个领域感兴趣。)
He has a degree in marketing, having majored in the subject. (他拥有市场营销学位，主修这门课程。)