Anchor: A mountain biker rides a trail through the woods.
Entailed: A biker rides through the forest.
Contradiction: The biker is riding down the sidewalk.
Contradiction: You should always wear your seatbelt. 
Contradiction: a person doing a leap
Contradiction: A dark haired boy is drinking a soda.
Contradiction: The estimate of resources needed will be too high if a capacity factor of 85 percent is assumed.