Riddle #134

Question: You have a glass of water that looks about half full. How can you tell, only using the glass of water itself, if the glass is half full or not?

The glass is a right cylinder.

Question: What tastes better than it smells?

Question: What loses its head in the morning and gets it back at night?

Question: What two things can you never eat for breakfast?

Question: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?

Question: What asks but never answers?