Anchor: For health reasons, it is best to avoid swimming in rivers, ponds, lakes, and reservoirs your body is unlikely to be able to deal with some of the other things swimming around with you.
Entailed: It is best to not swim in the natural water.
Contradiction: You should definitely swim in the local rivers.
Contradiction: They get it.
Contradiction: Teen rides snowboard down stairs.
Contradiction: The sweather is blue
Contradiction: A dog is fetching.