Answer:
Though I am only two words I have thousands of letters in me
What do you call a pig that is no fun to be around?
I tremble at each breath of air and yet can heaviest burdens bear.
I can fall off a building and live, but in water I will die. What am I?
Taken from a mine and then locked up in a wooden case. I am used by students everyday.
Brings the sky a lot closer.