On the corresponding relationship between entering tone in ancient Chinese and tone in modern Chinese.

A: The tone category system of modern Chinese is inherited from ancient Chinese. There were four tones of "Ping, Shang, Qu and Ru" in the Qi and Liang Dynasties in the Southern Dynasties in China, which were later divided according to the voiced initials. The ancient voiced initials all belong to the yin tone, and the ancient voiced initials all belong to the yang tone. In this way, the four tones in ancient times are actually divided into eight categories: "Yin Ping, rising tone, rising tone, rising tone, rising tone, singing tone, singing tone, entering tone and entering tone". The division and combination of this tone system in modern Chinese dialects are not exactly the same. As far as the tone of Putonghua is concerned, its flat sound is equivalent to the flat sound of ancient voiced initials, and its flat sound is equivalent to the flat sound of ancient voiced initials. Its upper voice includes another part of the upper voice of the ancient voiced initials.

The ancient Rusheng characters have disappeared in Putonghua. The initial consonants of the ancient entering tone have evolved into four tones in Putonghua, namely, flat tone, rising tone, rising tone and falling tone, but they lack regularity. The initial consonants of ancient entering tone are pronounced as rising tone and falling tone respectively in Putonghua.