Quartz is quartz—a silicon ion surrounded by four oxygen ions—there's no difference at all between two-million-year-old Pleistocene quartz and Cambrian quartz created over 500 million years ago.
He came across the jawbone of a 4.5 million-year-old marsupial.
他偶然发现了一个450万年前的有袋动物的颌骨。
《柯林斯英汉双解大词典》
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One interpretation regarding the absence of fossils during this important 100-million-year period is that early animals were soft-bodied and simply did not fossilize.