How many ears do you have?
I have two ears.
What is it?
It's an eye.
How many eyes do you have?
I have two eyes.
What is it?
It's a mouth.
What is it?
It's a nose.
How many mouths do you have?
I have one mouth.
How many noses do you have?
I have one nose.
What is it?
It's an ear.
