阅读理解At just 40 years old, hip-hopstar Kasseem Dean, more popularly known as Swizz Beatz, has amassed (积累) a track record, lifestyle and nearly $ 70 million net worth thatwould inspire most of us to retire early. So why does Dean continue to both workextremely hard and try projects that come with the risk of rejection (拒绝)?During our interview for UncommonDrive, a video series for USA & Main that seeks to find out the motivationsand magic of world-class business people, Dean provided a memorable answer: Youonly have so much time — once it's gone you don't get it back. Don'