Answer:
What is always coming but never arrives?
What has many keys but cannot open a single lock or door?
What word is always pronounced wrong?
What occurs once in a minute, twice in a moment and never in one thousand years?
They can be long or short; they can be grown or bought; they can be painted or left bare; they can be round or square.
It produces a flower but it is not its fruit; it produces branches which are its fruit.