求助：situation ,circumstance,environment之间,意思和用法有什么区别?

surrounding常用复数形式,指"环境,周围的事物",词义较狭窄,仅指周围的具体的物质性的东西.
The students live happily in beautiful surroundings.
environment意为"环境,周围状况,自然环境"一个生物体或一群生物体周围的整体状况,尤其指作用和影响这群生物体的生长,发展和生存的外界物质条件的总和.
The twins were separated at birth and brought up in entirely different environment.
circumstance意为"环境,情形,情况",常用复数形式,表明与某事件或某人有关的情况,环境,境况等.
He was forced by circumstances to do this.