Anchor: A group of people are running a marathon in winter.
Entailed: the people are running in a group a long a course.
Contradiction: The group of people are running a marathon during the summer.
Contradiction: A group of people watching TV.
Contradiction: We would get a notice in the mail that said we could not use that one anymore.  
Contradiction: A man is throwing ketchup at a concert.
Contradiction: The men are leading the horses.