Our respiratory system ? lungs and associated passageways ? snags the oxygen from the air , passes it along to the transporters in our bloodstream , drags the carbon dioxide ( one of the byproducts of cell life ) back out of the blood and expels it out into the air 呼吸系統(tǒng)? ?肺、以及相聯(lián)的各個通道? ?從空氣中吸入氧氣,通過循環(huán)系統(tǒng)把他們輸送到血液里,把二氧化碳(細胞的副產(chǎn)品)從血液里呼吸出去,排放到空氣。