century

这座古堡建于16世纪。

This castle was built in the 16th ___century.

这台收音机是上个世纪的产物。

This radio is a product of the last ___century.

这些建筑物已经有几百年的历史了。

These buildings are ___centuries old.

我们生活在21世纪。

We live in the 21st ___century.