Mars has an insubstantial atmosphere, consisting almost entirely of carbon dioxide.
火星周围有一个薄薄的大气层，几乎全由二氧化碳构成。
《柯林斯英汉双解大词典》
2
The atmosphere of Mars could not support life.
生命无法在火星的大气环境下生存。
《牛津词典》
3
The absence of an oxygen atmosphere on Mars and other planets in our solar system means that these planets also lack an ozone shield that would protect surface-dwelling life from UV radiation.