但是，他们之所以又被视为化石燃料，主要还是因为它们是由史前时代的动植物经腐烂后埋藏在地下数百万年而成的。

But they are known as fossil fuels because they are made from decomposed plants and animals that have been buried in the ground for millions of years.

youdao

但是，他们之所以又被视为化石燃料，主要还是因为它们是由史前时代的动植物经腐烂后埋藏在地下数百万年而成的。

But they are known as fossil fuels because they are made from decomposed plants and animals that have been buried in the ground for millions of years.

youdao