真空包装的火腿片应在食用前30分钟把包装除去。Vacuum-packed ham slices should be unwrapped 30 minutes before serving.直接邮寄广告业在特卖品的包装方面已经变得非常熟练了。The direct marketing industry has become adept at packaging special offers.然后那些咖啡豆被磨碎，包装好作为咖啡粉出售。The...
Ozone is a highly reactive form of oxygen gas.臭氧是一种非常活跃的氧气形态。Ozone is produced by the reaction between oxygen and ultra-violet light.臭氧由氧气和紫外线发生反应而产生。Carbon, hydrogen and oxygen combine chemically to form carbohydrates a...