positive externality的用法和样例：
例句
- Occasionally, I buylaunch my own fireworks, generating cheerful positive externalities.
我自己偶尔会买点焰火来放，产生令人愉悦的正外部性。 - 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，我怀疑那些不知道焰火表演将何时开始的远邻，是否会如你所想的那样欣赏焰火表演。
