1. 氧；氧气
Oxygen is a colourless gas that exists in large quantities in the air. All plants and animals need oxygen in order to live.
oxygen
e.g. The human brain needs to be without oxygen for only four minutes before permanent damage occurs.
人的大脑缺氧4分钟后便会造成永久性损伤。
1. 氧；氧气
Oxygen is a colourless gas that exists in large quantities in the air. All plants and animals need oxygen in order to live.
oxygen
e.g. The human brain needs to be without oxygen for only four minutes before permanent damage occurs.
人的大脑缺氧4分钟后便会造成永久性损伤。
