Answer:
I am made of wood but can't be sawed? What am I?
If you drop me I'm sure to crack. But give me a smile and I'll always smile back.
Never ahead, ever behind, yet flying swiftly past, for a child, I last forever, for adults, I'm gone too fast.
I get dirty when wiping things clean. What am I?
What five-letter word becomes shorter when you add two letters to it?
What did the piece of wood say when he saw the screwdriver and screws approaching?