I have done a hand-drawn animation illustration and original painting design before. The terminology you said is not quite the same as what I learned, but the teacher also told us these action theories. Teachers often give us examples with Disney animations. I will answer them roughly according to my memory. 1, preparatory action: For example, if a person is boxing, he should swing a punch. Then, according to Disney's original painting design theory, this person should swing backwards, then stretch forward, and then stretch his arm forward. Swinging backwards is a preparatory action. The teacher said that this is called "to rise first, to restrain", that is, if you want to stretch forward, you have to retreat one by one. If you want to retreat, you must stretch forward first. 2. Follow-up action: The boxer swings his arm, which is a follow-up action. 3. Inertia: After the fist hits the enemy, it will continue to swing forward with inertia. This is inertia. Or the act of throwing stones. After the stone is shot, the arm naturally hangs down and the inertia swings backwards. This is inertia. 4, elastic action: the most typical example is the ball landing. The ball is actually round in the process of falling, but it will be drawn as a vertical oval in the animation and elongated. When the ball hits the ground, it will become a horizontal oval, that is, a flat fall. This is done to better highlight the elastic effect of the ball. There is also the Monkey King's golden hoop, which should be straight normally when waved, but it will bend with the direction of action in order to highlight the effect. 5. Curved motion: There are two kinds of curved motion, one is the shaking of animal tail. For example, the tail of a cow always moves in a small range at the root of the tail and in a large range at the tip of the tail, so that the S-shaped movement will be repeated. There is also a carp swimming in the water. When we observe from above, the fish's body and swimming route will also show a curve process. 6. Exaggeration: When a cat in Tom and Jerry sees a dog, its eyes will pop out and its mouth will get bigger, almost touching the ground. This is exaggeration. The above theoretical knowledge is what I have learned before, so I may not explain it in detail. I hope it helps you.