Interpretation of ancient Chinese phonetics such as Jixie and Wuyu: Look at the right half of the two words first. The two words "Wu Oh" and "Zuzoh" are typical entering tone words (non-tone and rising tone), which can be verified in ancient Chinese phonology. Therefore, the "nasty" and "nasty" after adding radicals are obviously entering tones, not falling tones of Mandarin. The word "nasty" is the most commonly used word in Wu dialect area today. Meng Jiao (Huzhou), Gui Youguang (Kunshan) and Wang Mian (Shaoxing), the original users of this word, are all from Jiangnan, Jiangsu and Zhejiang. So there is no objection in the case of pronouncing "oh coh". Objectively speaking, there is no entering tone in Mandarin, so the pronunciation of many words needs to be discussed.