Riddle: What's Boss Wang's answer of buying a drink?

Li Xiu is good at wine tasting and guessing. One day, as usual, he came to Taibailou Hotel. When boss Wang saw that it was Li Xiucai, he smiled and said, "I'll do a crossword puzzle." After talking, he said: "Tang Yu has it, Yao Shun has it; Yes and no in Shang and Zhou Dynasties. " Li Xiucai said, "I also want to make your answer a mystery. Do you think it's right: there are people who jump, but there are no people who walk; There are tall ones and short ones. There are wise men, but no fools. On the right, but not on the left; There is cold weather, but there is no hot weather. " Boss Wang laughed, put on a sumptuous banquet and invited Li Xiucai to drink heartily. Do you know what this word is? Answer: mouth