和弦

These are the opening chords of a sonata.

这些是奏鸣曲起始。

That the note relation in semitone and chords sequence gained attention and usage step by step along with the harmony chromaticism.

声半音化进程中，半音中音关系连接性质也发生了一些化。

The plagal cadence, sometimes known as the Amen cadence from ecclesiastical use, is the progression from the chord of the subdominant to the tonic, IV - I.

格终止，有时也被称为源于教会“阿们终止”，是指从下属音到主音进行，IV–I。