Good Riddles

Question: If it takes three men two days to dig a hole, how long does it take one man to dig half of a hole?

Question: It turns into a different story.

What is it?

Question: What was the president of the United State's name in 1980?

Question: A trail, a union, together tied.
Come across me and you will find,
you cannot change the course I'm on,
without me you cannot travel on.

What am I?

Question: One falls but never breaks and the other breaks but never falls?

What are they?