If you have it, you want to share it. If you share it, you don't have it.
What is a secret?
What (food) has no beginning, end, or middle?
A doughnut.
You answer me, though I never ask you questions.
What is a (tele)phone?
The highest mountain on earth before Mount Everest was discovered.
What is Mount Everest?
The more you have of it, the less you see.
What is darkness?
It has to be broken (that's "cracked") before it can be used.
What is an egg.
It goes up and never comes down.
What is your age?
It is harder to catch the faster you run.
What is your breath?
It is tall when it is young and short when it is old.
What is a candle, or a used pencil.
The more it dries, the wetter it gets.
What is a towel, or a sponge?
It is always in front of you but can’t be seen.
What is the future?
It stays where it is when it goes off.
What is an alarm clock?
It gets whiter the dirtier it gets.
What is a chalkboard?
The number of bricks takes to complete a building made of bricks.
What is one? The last one.
It only has two words, but contains the most letters of all.
What is a post office?
You heard me before, yet you hear me again. Then I die, 'til you call me again.
What is an echo?
How many letters are in the alphabet (in standard English)?
What is 11: t-h-e-a-l-p-h-a-b-e-t !
A question that you can never answer yes to.
What is "Are you asleep"?
It is as big as a plate, as deep as a cup, but not even water can fill it up.
What is a (pasta) strainer?
The value of the moon (in US coinage terms).
What is $1, because the moon has 4 quarters.