Anchor: But unless the salamander works, his chances are only slight."  There was a mutter of agreement from others, before an older voice broke in.
Entailed: The salamander has to work or he doesn't have much of a chance.
Contradiction: He had good odds even without the salamander.
Contradiction: Two girls riding bikes.
Contradiction: The child is playing.
Contradiction: A sales clerk ringing up a sale.
Contradiction: Not taking all the precautions necessary produces two effects.