久青草国产手机视频免费观看_毛片网站是多少_亚洲视频中文_一区二区高清在线

hydrogen

英 ['ha?dr?d?(?)n] 美['ha?dr?d??n]
  • n. [化學(xué)] 氫

英英釋意


1. a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe