Anchor: A guy and boy are riding on a skateboard together.
Entailed: The 2 people could fall down on top of each other easily.
Contradiction: The 2 guys are rollerblading around the park a few feet away from each other.
Contradiction: A man is talking on the cell phone
Contradiction: Reevaluating gear, capital property, and plant matter. 
Contradiction: They would need to have at least three months worth of sailing practice before taking a boat out on their own.
Contradiction: My son had poison ivy so he needed to see a doctor.