和弦

These are the opening chords of a sonata.

这些是奏鸣曲的起始。

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

半化的进程中，半中关系连接的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的“阿们终止”，是指从下属到主的进行，IV–I。