"The basic thinking behind environmental protection is very simple--reduce, reuse, recover, recycle," says Yao Kuan-mu, illustrating with the four R's.
「環保原理很簡單﹘ ﹘減量（reduce）、重覆使用（reuse）、回收（recovery）和再生（recycle）」，姚關穆以 4R 說明。