空气一种无色、无嗅、无味的气体混合物，主要由氮气（约占78％）和氧气（约占21％）组成，还有少量的氩、二氧化碳、氢、氖、氦及其它气体 A colorless, odorless, tasteless, gaseous mixture, mainly nitrogen(approximately78 percent) and oxygen(approximately21 percent) with lesser amounts of argon, carbon dioxide, hydrogen, neon, helium, and other gases.