Answer:
What is black when you buy it red when you use it and gray when you throw it away?
Take away my first letter take away my second letter take away all my letters and I would remain the same.
I tremble at each breath of air and yet can heaviest burdens bear.
What goes up and down stairs without moving?
You turn me over after you have traveled far. What am I?
When is it bad luck to see a black cat?