水的密度为ρ=1.0×103kg/m3,将一杯水倒出一半以后,剩余水的密度为____g/cm3.体积为0.5m3的钢瓶内装有密度为6kg/m3的氧气,某次电焊中用去了其中的1/3,则剩余氧气的密度为____kg/m3.
——It won't take long to clean our school if all the students are willing to help. ——Yes, I think so. ________.
血液中运输氧气的细胞是 ____ .