Answer:
You can catch me but cannot throw me.
A piece of paper that takes most people 3 or 4 years to get.
You throw me away, I find my way back. Traditionally, I'm wooden with an arch in my back. What am I?
I go through a door but never go in and never come out.
I'm where yesterday follows today and tomorrow is in the middle. What am I?
What made Cyclops quit teaching?