同学你好，该知识点来自沪江网校《【Uni智能】托福签95冲105分名师VIP-大学起点【开学季专享签约班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
三个词都是表示转折，意思很相近
whereas “鉴于”，“然而”，用于同一句中两个相反的意见，前面加逗号，较为正式，语气和however强弱差不多
例如：Some people believe that schools are responsible for the behavior of their students, whereas others argue that argue that discipline is the responsibility of parents.

however,“然而”，一般用于句首，但也可以用于句中句末，用来表达与前一句相反的意思，后面打逗号
例如：Some people believe that schools are responsible for the behavior of their students. However, others argue that argue that discipline is the responsibility of parents.

but，“但是”，与however一样都引出并列句，但是表达转折的语气最强，而且but后不加逗号
例如：Mary likes classical music but her husband likes rock music.

祝学习愉快~