代表キーワード :: 水資源
資料:1件
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Earth, the Water Planet
- The earth is called a water planet because more than 70% of its surface is water. About a 1.4 billion cubic kilometers of water cover the earth. People live their lives enjoying the benefits of water while having to fight with water from time to time. We use w...
550 販売中 2006/02/15- 閲覧(1,541)
