Answer:
What is the saddest fruit?
A man who was outside in the rain without an umbrella or hat didn't get a single hair on his head wet. Why?
What goes around the wood but never goes into the wood?
I'm where yesterday follows today and tomorrow is in the middle. What am I?
I go up and down at the same time. Up towards to sky and down towards the ground. What am I?
No matter how little or how much you use me, you change me every month.