Answer:
The more you take, the more you leave behind.
No matter how little or how much you use me, you change me every month.
What stays on the ground but never gets dirty?
What is that which, though black itself, enlightens the world without burning?
Two in a whole and four in a pair. And six in a trio you see. And eight's a quartet but what you must get. Is the name that fits just one of me?
What did the piece of wood say when he saw the screwdriver and screws approaching?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?