Studies support the theory that there are several causes, instead of a single environmental cause or genetic problem.

VOA: special.2009.01.06

I'm considering majoring in Urban Studies and Environmental studies.

我准备学习城市研究和环境研究。

纽约很棒 - SpeakingMax英语口语达人

I'm taking a class called AP Environmental Studies,

我选的一个课程叫做大气规划环境研究，

高中生活怎么样？ - SpeakingMax英语口语达人

The studies also appear to show that environmental causes such as viruses or bacteria may be involved.

VOA: special.2009.01.06

It was based on three separate studies by a partnership of government agencies and environmental groups.

VOA: special.2009.05.12