| 1. | Plants absorb oxygen . |
| 植物吸收氧气。
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| 2. | Iron adsorbs oxygen . |
| 铁能吸附氧。
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| 3. | Two atoms of hydrogen combine with one atom of oxygen to form a molecule of water. |
| 两个氢原子和一个氧原子结合而形成一个水分子。
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| 4. | Water is composed of the elements hydrogen and oxygen . |
| 水是由氢元素和氧元素组成的。
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| 5. | A molecule of water consists of two atoms of hydrogen and one atom of oxygen . |
| 水分子含有两个氢原子和一个氧原子。
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| 6. | Hydrogen and oxygen are gases. |
| 氢和氧都是气体。
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| 7. | Hydrogen and oxygen combine/Hydrogen combines with oxygen to form water. |
| 氢与氧化合成水。
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| 8. | Water is composed of hydrogen and oxygen . |
| 水是由氢和氧化合而成的。
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| 9. | Fish take in oxygen through their gills. |
| 鱼通过鳃摄取氧气。
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| 10. | There was a shortage of oxygen at the top of the mountain. |
| 该山顶上缺氧。
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