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...
I hate that they should be worried about trifles.真遗憾,他们竟为区区小事发愁.And should we be worried about Obama's mountainous self - confidence ?我们是否也应该反思一下奥巴马过人的 自信 呢 ?I hate that they should be worried [ them to be worried ]...