Simplify the following text for a Grade 10 native English-speaking person.
Original: In his catalogue to Life through the Ages ( 1946 ) , he reiterated views that he had written earlier ( Knight , 1935 ) , describing the great beasts as `` slow-moving dunces '' that were `` unadaptable and unprogressive '' while conceding that small dinosaurs had been more active .
Simplified: In his catalogue to Life through the Ages ( 1946 ) , he repeated views he had written earlier ( Knight , 1935 ) . He described the great beasts as `` slow-moving dunces '' that were `` unadaptable and unprogressive '' while conceding that small dinosaurs may have been more active .