positive externality的用法和樣例：
例句
- Occasionally, I buylaunch my own fireworks, generating cheerful positive externalities.
我自己偶爾會買點焰火來放，產生令人愉悅的正外部性。 - On the positive externality side, I doubt that more distant neighbours enjoy the show as much as you think, not knowing when it is going to start.
就正外部性而言，我懷疑那些不知道焰火表演將何時開始的遠鄰，是否會如你所想的那樣欣賞焰火表演。
