Anchor: A group of girls are riding on a roller coaster.
Entailed: Girls are on a roller coaster.
Contradiction: No one is on the roller coaster.
Contradiction: A woman is sitting in the library.
Contradiction: Soldiers from the Vietnam War spent lots of money during the Wan Chai boom.  
Contradiction: A girl plays in the snow.
Contradiction: The footpaths trail from the peak of Skiddaw.