Complex sentence: Dr. Zaius admits that he has always known that human civilization existed long before apes ruled the planet and "the Forbidden Zone was once a paradise, (man) made a desert of it... ages ago!".
Split into simpler sentences: Dr. Zaius admits that he has always known that human civilization existed long before apes ruled the planet. He explains that "the Forbidden Zone was once a paradise, (man) made a desert of it... ages ago!".