Anchor: Your friends should have been here by now, shouldn't they?  
Entailed: Shouldn't your friends already be here?
Contradiction: It's good that your friends are already here.
Contradiction: Cynthia was allergic to the grass, and wouldn't touch it.
Contradiction: Two women sit on steps.
Contradiction: The child is asleep in the crib.
Contradiction: They are playing football.