Anchor: Natural fertility was enhanced by Europe's most advanced systems of irrigation, still operating in the medieval canals that you'll see on your way south to Pavia.
Entailed: Natural fertility was increased by Europe's systems of irrigation, still using the medieval canals that will be visible en route south to Pavia.
Contradiction: Natural fertility was not enhanced by advanced systems of irrigation.
Contradiction: Polycrates was a timid leader around the time of 60 AD.
Contradiction: A woman makes a drawer out of cardboard.
Contradiction: The sky was green and the trees were blue.
Contradiction: Boys are having fun at the park.