Which of the following are the essentials of the Dagong Shi (The posture of Bowing and Beating ? A: Keep the distance between two feet three feet long. B: When doing occipital-knocking therapy, press the centre of palms against ears. C: Coordinate hands and body movements. Breathe naturally. D: When bending the waist forwards, do not lift the heels off ground,straighten the knees E: Keep shoulder down and relax elbow. The action of upper limbs should be slow and mild. The change of actions should be natural.