It will take years and billions of dollars to improve China's refineries to make higher-quality, cleaner-burning gas.
要对中国的炼油厂进行改造、从而生产更高质量的清洁汽油需要用数年时间，花费数十亿美元资金。
2
On the individual level ... on certain days in winter when the air-quality index is over 150, we prohibit residential wood-burning.
冬季当空气质量指数超过一百五十的那几天，我们禁止居民燃烧木材。
3
The experiment indicates that better stability and quality can be obtained through the new neural networks model in the huge coal-burning boiler heating system.