Anchor: A dirt biker on a sand dune.
Entailed: There is a dirt biker on a sand dune.
Contradiction: There is a race car driver on a sand dune.
Contradiction: I was demoted in the fifth month. 
Contradiction: A city street is crowded.
Contradiction: We'll get that fixed. 
Contradiction: I took a trip across the Mohave Desert when I went to Las Vegas.