Pingsheng: gradually divided into two tones: Yin Pingping and Yang Pingping.
Shangsheng: It's time for future generations to have no sound.
De-voiced: De-voiced the offspring.
Rusheng: This is a short tone, and modern Chinese has three tones: flat, up and down.
The four tones of poetry can be divided into two categories: flat tone, that is, flat tone, and flat tone, that is, three tones.
In the present understanding, ping is the first sound and the second sound; It's the third sound and the fourth sound.