Six Brilliant Doubts

Six Brilliant Doubts !

1. If all the nations in the world are in debt,where did all the money go?

2. When dog food is new with improved taste,who testsd it? 

3. If the "black box" flight recorder is never damaged during a plane crash,why isn't the whole airplane made out of that stuff?

4. Who copyrighte the copyright symbol?

5. Can you cry under water?

6. Why do people say "you've been working like a dog" while dogs just sit around all day.@