What I want to point out to you is this part of her letter, the third paragraph here, where she says, "My idea is this."

大家来看,信的第三段,她说，“我认为“

耶鲁公开课 - 1945年后的美国小说课程节选

We'll be talking about the fact that this is an interval of a third; it spans three letter names a little bit later on.

我们以后会谈到,这其实是个三度音程,它跨越了三个音名

耶鲁公开课 - 聆听音乐课程节选