Anchor: Coeds sit on a stone picnic table and eat lunch in the courtyard.
Entailed: People sit on a picnic table and eat lunch.
Contradiction: People sit on a wooden picnic table and eat lunch in the courtyard.
Contradiction: my wife no longer has a sailboat, she sold it last year
Contradiction: Someone washing dishes.
Contradiction: The players were on a bus which broke down on the highway
Contradiction: A boy is running.