Answer:
Three little letters, a paradox to some. The worse that it is, the better it becomes.
What is long and slim, works in light. Has but one eye, and an awful bite?
Who makes it, has no need of it. Who buys it, has no use for it. Who uses it can neither see nor feel it. What is it?
It's usually found dried, but often kept slicker. Above another need, it's said to be thicker. What is it?
It is able to speak because it has a hard gone. You know what it is as soon as it has sung. What is it?
What did the piece of wood say when he saw the screwdriver and screws approaching?