Anchor: A guy sitting on a chair tunes his guitar.
Entailed: A man is tuning an instrument while sitting down.
Contradiction: A man is playing a violin.
Contradiction: He isn't great at the flute, which somewhat ruined the atmosphere when he played Danny Boy. 
Contradiction: Do we keep refining as we go along?
Contradiction: There are many people watching a tennis match.
Contradiction: A woman is sleeping at night.