There are no sharps or flats in the key of C major.

C大调中没有升半音和降半音。

《牛津词典》

Buy a 10 hole harmonica in the key of c, then start with the first lesson.

所以购买一支C调的10孔口琴吧，然后开始你的第一课。

youdao

Right! Make sure to buy a harmonica in the key of C. If problem, friends will help you in the forum.

是的，买一把十孔口琴，一定是C调的，然后跟着教程学习就可以了，有问题，大家可以在论坛帮助解决。

youdao

Let's say we're in the key of C here.

让我们看看C调的情况

耶鲁公开课 - 聆听音乐课程节选

We've got some chords set out and we're going to-- we've got some chords set out here and we're in the key of C at this point, and we're going to hear Beethoven go to a tonic chord, then a sub-dominant chord, then a tonic chord, then a dominant chord and so on.

我们看到有一些和弦-,而我们现在在C调的位置上，然后听贝多芬的主音和弦，然后是次属音和弦，然后是主音和弦，接着是属音和弦，如此往复。

耶鲁公开课 - 聆听音乐课程节选

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