Answer:
With three leaves, I am just a plant. Add another leaf and everyone will want me for good luck. What am I?
I make a loud sound when I'm changing. When I do change I get bigger but weigh less. What am I?
My snake-like body cracks and burns. I cause pain but pleasure too. What am I?
I am a chair that can move. What am I?
I am a cold man without a soul. If there is warmth in me, it slowly will kill me. What am I?
When is it bad luck to see a black cat?