Rather than thinking of a teacher necessarily, one can think of an individual acts more like a mentor or coach in certain settings.

不必要一定要有个老师，你可以想成一个人在某个领域,作为指导者或是教练。

麻省理工公开课 - 媒体、教育、市场课程节选

I can remember in high school. I had a really forward thinking English teacher

我记得在高中，我有一个思想很前卫的英语老师。

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