external cost的用法和樣例：
例句
用作名詞 (n.)
- The activity of traffic gives advantage to the society, but at the same time it also brings some adverse effects, which produce the exterior cost of traffic.
摘要交通活動(dòng)給人們的生活提供了便利，同時(shí)也給自然環(huán)境和社會(huì )帶來(lái)一定的負面影響，即產(chǎn)生了交通的外部成本。
