Anchor: They wouldn't be able to keep the mines secret very long, but the longer the better.
Entailed: They wouldn't be able to keep the mines a secret for very long.
Contradiction: They should have no problem keeping the mines a secret.
Contradiction: The bird is flying over an ocean.
Contradiction: Home runs that are hit that far can't be line drives.
Contradiction: I don't remember anything from my childhood
Contradiction: The dog is moving.