First, the correct way to write the vowel o: write it counterclockwise from the top, then overlap with the top and write it all at once. O when pronouncing, the mouth is half closed, the tongue is half high, the tongue is retracted and the lips are round.
Second, the two phonetic segments of vowel O are: bo, po, molo, yo, wo and fo. The three phonetic segments of vowel O are: Duo, Tuo, Nuo, Luo, Guo, Kuo, Huo, Zhuo, Zhuo, Shuo, Zuo, Cuo and Shuo.
Tongue twister of vowel O: An old woman came from the south slope with two baskets in her hand. The basket in her left hand is full of pineapples and the basket in her right hand is full of radishes. I don't know whether there are more pineapples in the basket in her left hand or in the basket in her right hand. It is right for you to send you pineapples and radishes, but it is wrong for you to carry a basket up the mountain.
Fourth, expand information:
The initial p and the final o form the syllable po, and the pinyin is p not. Examples of Chinese characters are: parking, splashing water.
The initial p and the final o form the syllable po, and the disyllabic pinyin pó. Examples of Chinese characters are: breaking and changing.
The initial p and the final o form the syllable po, and the three-tone pinyin pǒ. Examples of Chinese characters are "Yi" and "Yi".
The initial p and the final o form the syllable po, and the four-tone pinyin pà. The example of Chinese characters is forcibly broken.