Answer:
What is so delicate that even mentioning it breaks it?
What is broken if you say its name?
What body part is pronounced as one letter but written with three, only two different letters are used?
What is born on the ground but floats to the sky, to be returned back again from the clouds up high?
The line a runner strives to reach
Two little holes in the side of a hill. Just as you come to the cherry-red mill.