Anchor: He went to his desk and saw his boss working on the computer.
Entailed: His boss was doing something on the computer.
Contradiction: His boss was outside mowing the lawn.
Contradiction: A surfer is at a bar.
Contradiction: The 18-hole golf course at Discovery Bay is open to visitors Monday, Tuesday, and Friday. 
Contradiction: A truck site idly in a garage.
Contradiction: I felt dumb.