When singing with the abdomen and diaphragm, it is just an inner feeling, that is, knowing the specific position, without inner feeling, it is impossible to mobilize these two abstract organs. What is said upstairs is quite right. The abdomen is three inches below the navel. When you try to tuck in your abdomen, the concave part in the middle is your abdomen, and the diaphragm is where you take a deep breath. When your body expands like a balloon, the bottom of the balloon is where the diaphragm is. Only practice more and feel more.