2. You must choose a desk and chair with ergonomic design, use a special computer chair, and sit on it to follow the "three right angles": the first right angle is formed at the knee under the computer desk, the second right angle is formed between the thigh and the back, and the third right angle is formed at the elbow. Lean your shoulder blades against the back of the chair, put your shoulders down and keep your chin away from your neck. Look straight at the center of the computer screen, preferably with a supported chair back and armrest, and the height can be adjusted.