"major in environmental engineering" 是表示"主修环境工程"的英文表达。
来源："major" 是指"主修"的意思，而"environmental engineering" 是指"环境工程"的意思。
例句：
He is majoring in environmental engineering at the University of Capfornia, Berkeley.
(他正在加州大学伯克利分校主修环境工程。)
She has a degree in environmental engineering and is now working as an environmental consultant.
(她拥有环境工程学位，现在是环境顾问。)
The curriculum for the major in environmental engineering covers topics such as air pollution control and waste management.
(主修环境工程的课程涵盖了诸如空气污染控制和废弃物管理等话题。)