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》
2
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.
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.