We ____ in oxygen in the air

We ____ in oxygen in the air When we breathe,the oxygen in the air（） with our blood and g We need oxygen in air to maintain our lives. The ___ of oxygen in the air rises, and at last the air beco Trees take in harmful gases from the air ang produce oxygen o ____ out,in the open air We can get f___ air in the open air. As is known,the oxygen we breathe in mixes with our blood an ____ ____ ____ stay in the room with the air-condiioner in s in the open air in the air是什么意思 stick in the air