By fossils, we mean traces of prehistoric animals such as bones, which become mineralized, or impressions of bones or organs that are left in stone. — 提到化石,我们指的是史前生物的遗迹,比如已经矿化的骨头,或者是骨头或器官在石头上留下的印记。
① prehistoric /ˌpriːhɪˈstɔːrɪk/ a. 史前的;陈旧的
② mineralize /ˈmɪnərəˌlaɪz/ vt. 使矿物化