Liu Yun's method is to stretch the upper soft palate (the interior of the upper dentition) upward by airflow. Push the soft palate up with a small mirror. The doctor asked you to say "ah" when he examined your mouth. Or expectoration, or other means. Don't be fooled, it doesn't work at all. Small tongue shouted when he wanted to move, demanding that the louder the better, hahaha. It is required to exercise for two hours every day. By Liu Yun's own admission, this exercise method will be heard by others, and you will be called crazy. How can this method, which seriously interferes with other people's lives, work even if it has a little effect? Think about it, even if others don't say you are crazy, can you live forever and cure all diseases?