Answer:
Two brothers we are, great burdens we bear. All day we are bitterly pressed. Yet this I will say, we are full all the day, and empty when go to rest.
You must keep this thing. Its loss will affect your brothers. For once yours is lost, it will soon be lost by others.
Brown I am and much admired; many horses have I tried; tire a horse and worry a man; tell me this riddle if you can.
I am the yellow hem of the sea's blue skirt.
Three little letters, a paradox to some. The worse that it is, the better it becomes.
Why is the letter B always cool?