fossil

这块岩石里保存着一只古代鱼类的化石。

The rock contains a ___fossil of an ancient fish.

这台打印机真是个老古董，早就该换成新的了。

This printer is a real ___fossil and should have been replaced long ago.

我们远足时发现了一块因雨水侵蚀而露出地表的小化石。

We found a small ___fossil that rainwater erosion had exposed during our hike.