Anchor: A boy is doing a skateboard trick on the boardwalk.
Entailed: The boy is skateboarding.
Contradiction: A skateboarder is riding a bike.
Contradiction: A boy is inside with his toy.
Contradiction: The boy is walking.
Contradiction: A baby is sitting on a skatebaord in the living room and moving along like a toy car
Contradiction: A boy skateboarding on the surface of the sun.