The medical sense of pain that humans can feel is divided into 12 levels, the higher the level, the greater the pain felt. Level 1: mosquito bites Level 2: surgery after anesthesia Level 3: friendly flirting between lovers Level 4: parents hate iron scolding Level 5: slapped with a slap, leaving red palm marks Level 6: gastroenteritis caused by inattention to diet, stomach pain Level 7: beaten with sticks, leaving black and purple marks Level 8: a variety of ways to cause extensive bleeding trauma Level 9: the pain of flesh and skin, tiger stool Level 10: caused by physical disability, such as war injuries were blown off fingers Level 11: visceral pain, it is said that the Soviet agents invented a method to force a confession, the towel twisted into a spiral, let people swallow, the towel to the stomach and stomach wall surrendered together Level 12: the feeling of the mother in childbirth