Anchor: A man and a boy riding bikes down a sidewalk.
Entailed: Two people are riding bikes outdoors.
Contradiction: Two people are playing air hockey on Mars.
Contradiction: The objects landed soundlessly against the metal. 
Contradiction: If the RWC is under 25%, the concentrations vary.
Contradiction: a man is on a rollercoaster
Contradiction: A farmer is outside looking at his land.