A positive externality occurs when a home owner repaints her house and plants (an attractive garden. ▣All the neighbors benefit from(受益于)this activity,yet the home owner's decision to repaint and landscape(从事自然美化工作) probably did not take these benefits into account,because his neighbors would not pay for the benefit ()  A positive externality occurs when a home owner repaints her house and plants (建立) an attractive garden.  All the neighbors benefit from (受益于) this activity, yet the home owner’s decision to repaint and landscape(从事自然美化工作) probably did not take these benefits into account, because his neighbors would not pay for the benefit (好处)