Anchor: a mountain biker riding on a hillside wearing a helmet.
Entailed: A person is riding a mountain bike.
Contradiction: A mountain biker is sitting on swing.
Contradiction: I prefer to go home first after work, then come back.
Contradiction: A log is lying along the beach.
Contradiction: The students were full of life and didn't need a new center opened just for them. 
Contradiction: I used to be involved with Girl Scouts.