Answer:
What can I not be tomorrow?
Feed me anything and I will live.. But feed me with water and I will die...
What always comes into a house through the keyhole?
You have a bucket full with 5 gallons of water. What can you ADD to it in order to make it 3 gallons?
What can you fill a room with that takes up no space?
Not born, but from a Mother's body drawn. I hang until half of me is gone. I sleep in a cave until I grow old. Then valued for my hardened gold.