What are the differences of motion tween and shape tween?

Answer 1

Both motion tweens and shape tweens are useful animation tools in Flash.

Shape tweens directly change an object's shape and/or color over a series of frames from the first keyframe to the second. This produces a fluid morphing effect. For a smooth transition from Keyframe A to Keyframe B, shape hints can be used to guide the tween during the animation. For example, putting a shape hint on a character's hand in both keyframes can prevent the hand from morphing into a part of the shoulder. Shape tweens can only be used on shapes that haven't already been converted into a symbol, or on shapes edited directly within symbols.

Motion tweens are used to animated and transform a symbol with a shape inside of it. Motion tweens are used most often to translate, scale, and rotate a symbol for an animation. There are different kinds of motion tweens which include movie, graphic, and button tweens. Graphic tweens are useful for quickly switching between two keyframes within the symbol with different shapes in them, to change things such as facial expressions, positions, and more.