The main goal of the respiratory system is to bring fresh in so that you can extract oxygen from it, and blow used air out so that you can rid of carbon dioxide which is the end product of carbon metabolism inside our bodies.

呼吸系统的主要功能是,吸入新鲜空气,以便获得空气中的氧气,呼出废气,以便排出二氧化碳,二氧化碳是人体内碳代谢的终产物

耶鲁公开课 - 生物医学工程探索课程节选

I try to come to the park early, you know, get some exercise and get a nice walk and some air.

我尽量早起去公园，去锻炼身体，散步，呼吸新鲜空气。

中央公园的时光 - SpeakingMax英语口语达人

We usually try to come to the park to get out a little bit, get some air,

我们通常尽量出去，去公园，呼吸新鲜空气，

中央公园的时光 - SpeakingMax英语口语达人

I want to have some fresh air.

我想呼吸点新鲜空气。

I want to 实战 - SpeakingMax英语口语达人