Anchor: As you know, the Roman and the Ottoman empires suffered from grave internal weaknesses but persisted for centuries.
Entailed: Despite serious internal weaknesses, the Roman empire persisted for centuries. 
Contradiction: No one realizes that the Roman empire had serious internal weaknesses. 
Contradiction: A group of women are waiting for the bus.
Contradiction: I wanted to have a wife and kids.
Contradiction: People are playing soccer.
Contradiction: The man is on the street.