原文 'AN APARTMENT OWNER WOULD PROVIDE AN EXTERNAL BENEFIT IF SHE INSTALLED A SMOKE DETECTOR. bUT SHE DOESNT CONSIDER HER NEIGHBOR'S MARGINAL BENEFIT WHEN SHE IS DECIDING WHETHER TO INSTALL A SMOKE DETECTOR. THERE IS UNDERPRODUCTION'
我不明白为什么 EXTERNAL BENEFIT 就会造成UDERPRODUCTION.
讲一下呗 |