heavily-polluted ★★★★
☆☆☆☆ ...
Although it was once a heavily-polluted rice field, it is now much cleaner.
儘管它曾經是一個污染嚴重的稻田,但現在卻變得更加乾淨。
28._____it was once a heavily-polluted r..-阿摩線上測驗