金石 きんせき併用 へいよう時代 じだいじゃありませんでした
kinsekie iyōjidaijārimasendeshita

Noun
Desu Copula

The polite, past negative form of 金石併用時代

1. It wasn't an age of using both metal and stone.; It wasn't a time when both metal and stone were used.

Past/Perfective
Negative
Polite
Terminal Form