Solid–definite shape and volume–think about an ice cube, as a solid the shape is set and so you can’t increase the space they take up

Liquid–no definite shape, but definite volume–think about a can of soda when you pour it into a glass it doesn’t have the same shape as the can, but the amount of soda was the same in the can as it is now in the glass

Gas–no definite shape or volume–think about a balloon the gas from your lungs take on the shape of the balloon and you can twist and turn that balloon into dozen of shapes.  Also you can put the balloon in the freezer and the (size) volume decreases and if you put it in the oven the volume (size) increases