n. a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust
n. 氧
[化] 氧O-2
1. Plants need oxygen to survive.
植物需要氧气才能生存。
2. We breathe in oxygen and exhale carbon dioxide.
我们吸入氧气，呼出二氧化碳。
3. The oxygen level in the water is important for fish.
水中的氧气水平对鱼类很重要。