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.

办公室里那些拒绝使用电脑的老员工简直就是活化石。

The older employees in the office who refuse to use computers are such ___fossils.

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.