Anchor: Put simply, 20 uninterrupted minutes are worth far more than 400 individually occurring three-second periods.
Entailed: Longer bouts of undivided attention are more useful than lots of unconnected short periods of attention. 
Contradiction: Equal amounts of time have the same benefits, no matter how they are broken up. 
Contradiction: A woman plays the guitar while she sings.
Contradiction: A man is wearing black and white
Contradiction: The books looked brand-new. 
Contradiction: A person sitting outside.