Hemoglobin, as you know, is an oxygen carrier and so red blood cells concentrate in bags of hemoglobin which circulate in your blood and they carry oxygen.

如你所知，血红蛋白是氧气的载体，所以红细胞集中在血红蛋白的袋子里，血红蛋白在血液中循环，它们携带氧气。