Answer:
What can be measured but not seen?
What do you fill with empty hands?
Two people are born at the same moment, but they don't have the same birthdays. How could this be?
The barber of New York shave all men in New York. No man living in New York is allowed to shave himself. The barber of Nee York lives in New York. Who shaves the barber ?
It's like food but water kills it. What is it?
If lightning strikes an orchestra who is the one most likely to get hit?