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卡片总数: 1 张•内容版本: v4•公开卡包•更新时间: 8/1/2026
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正面 (问题)
Oil, coal and natural gas are fossil fuels. How do fossil fuels form on Earth?
背面 (解答)
Fossil fuels are formed when dead plants and animals are broken down, buried and squeezed by heat and pressure over millions of years.