Allen Chen 懷想錄: 樂觀者和悲觀者對社會都有貢獻。樂觀者發明飛機，悲觀者發明降落傘。Both optimists and...

Allen Chen 懷想錄: 樂觀者和悲觀者對社會都有貢獻。樂觀者發明飛機，悲觀者發明降落傘。Both optimists and...: Both optimists and pessimists contribute to our society. The optimist invents the airplane and the pessimist the parachute.

樂觀者和悲觀者對社會都有貢...