“化石的”造句

科学家根据那些化石的骨骼结构确定其年代.
Scientists have dated the fossils by their bone structure.

有两个因素对生物化石的保存是有利的.
Tow factors are favorable for the preservation of organisms as fossils.

它们是怎样变成化石的?
How did they become fossils?

• #化石的