As you can see, there are a lot of keys in it.

正如你们所见,在它身上有很多音键

耶鲁公开课 - 聆听音乐课程节选

There are nine keys for my left thumb alone so I'm kind of switching between these on the back here and many others, and because of that I can go very high and I'll just demonstrate that.

我的左手拇指就要控制九个音键,通过按动后部,和其他地方的音键,我就能吹出很高的音,我现在就来演示

耶鲁公开课 - 聆听音乐课程节选