Long Riddles and Answers

Question: You bury me when I'm alive,
and dig me up only when I die.

What am I?

Question: If you have me, you want to share me. If you share me, you haven't got me. What am I?

Question: 20 people jump into an empty swimming pool but 24 heads come up. How did this happen?

Question: An item looks square from outside, Circle when opened and Triangle when taken out.

Question: One female dog goes in and there are no other dogs in there so why did dogs come out?