Anchor: A generic drug may prevent death by heart failure.
Entailed: Drugs can prevent people dying from heart failure.
Contradiction: Drugs are entirely ineffective in preventing deaths from heart failure.
Contradiction: While the park is filled with many amazing rock formation, no trees or ferns are anywhere nearby. 
Contradiction: People are sitting inside.
Contradiction: The women is sitting holding a cat.
Contradiction: A group of people play hockey.