2 sentences

1. 高海拔地区的空气稀薄，容易导致人体缺氧。

   gāo​hǎi​bá dì​qū de kōng​qì xī​bó, róng​yì dǎo​zhì rén​tǐ quē​yǎng.

   The air is thin at high altitudes, which can easily lead to hypoxia.

   Source: Dong Chinese Dictionary

2. 由于不适应高原上的稀薄空气，他刚到拉萨就感冒发烧了。

   yóu​yú bù shì​yìng gāo​yuán shàng de xī​bó kōng​qì, tā gāng dào Lā​sà jiù gǎn​mào fā​shāo le.

   Because he couldn't adjust to the thin air on the plateau, he caught a cold and developed a fever as soon as he arrived in Lhasa.

   Source: Dong Chinese Dictionary