Anchor: Normally they are safe, but on a rough day, take care.
Entailed: On a rough day, one needs to be careful.
Contradiction: Even on rough days, they are completely safe.
Contradiction: A group of people are complicit in their existence.
Contradiction: The kids play on the swings.
Contradiction: We don't do sea bakes and hate clams. 
Contradiction: The structure and functioning of terrestrial and aquatic ecological systems are regulated by nitrogen.