Answer:
Open me, and you can't see me without a mirror. Close me and you can't see me at all. What am I?
I have keys but no locks. I have space but no room. You can enter but can't go outside. What am I?
I am the noise Santa's reindeers make
I am sometimes referred to as chips
You are my brother, but I am not your brother. Who am I?
What language does a billboard speak?