我的名字叫空气,你看不见、摸不着我,但我一直伴随在你身边。我的家庭可算是历史悠久的大家庭了:氧、氮、二氧化碳三位成员是家庭的核心。千百年来,我一直在地球上默默地生活着。我的年龄虽然很大,人们发现我的时间也很长,但人们真正研究我、认清我的时间却很晚。人们曾长期把我看作一种单质,后来科学家们对我的组成做了深入研究才认识到,我并不是一 My name is air, you can not see, touch me, but I have been with you. My family can be a long-established family: the three members of oxygen, nitrogen and carbon dioxide are the heart of the family. For thousands of years, I have been living silently on Earth. My age is great, people find me a long time, but people really study me, recognize my time is late. People have long regarded me as a single element, and later scientists have done a thorough study of my composition to realize that I am not a