Chemical fossils (e.g. alkanes and porphyrins) are often the only evidence for life in rocks of PRECAMBRIAN age.是什么意思_Chemical fossils (e.g. alkanes and porphyrins) are often the only evidence for life in rocks of PRECAMBRIAN age.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句