These are the opening chords of a sonata.

这些是奏鸣曲的起始和弦。

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

在和声半音化的进程中，半音中音关系和弦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，有时也被称为于教会的“阿们终止”，是指从下属音和弦到主音和弦的进行，IV–I。