Hco
abbr. 重循環油（heavy cycle oil）
??? 情景例句
Are the beaches safe for swimming?
在這兒的海灘游泳安全嗎？
The rage of a wild boar is able to spoil more than one wood.
野豬一怒毀樹多。
As complaints must be made in writing, the Ombudsman receives an average of 1,200 letters a year.
由于意見均需用書面形式提出，司法特派員每年平均收到1，200封信。