Kids Riddles

Question: Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

Question: What's made of wood but can't be sawed?

Question: I give advice to others,
yet I know nothing myself.
I am a hitchhiker destined to stay still.

Question: The more you work, the more I'll eat.You keep me full, I'll keep you neat. What am I?

Question: My boots can fit though the green glass doors but my shoes cannot. Sea weed can fit but algae cannot. A tree can fit but a forest cannot. The moon can fit but a feather cannot. Why is this?