What is it?
Counterfeit money
Counterfeit money
If they're square it's possible for the cover to slip down the hole (diagonally). A round manhole cannot fall down no matter which way it is rotated because it's width in any direction is greater than the opening on the hole.
Romania (country).
One.
Because if 10 people eat 10 cakes in 10 days it means that each person eats a cake.
Teeth.
An echo
The future.
Rain.
A clock.
32
A bowling ball.
Bubble