金石 きんせき併用 へいよう じゃありませんでした
kinsekie iyōkija arimasendeshita

Noun
Desu Copula

The polite, past negative form of 金石併用期

1. It wasn't the period of using both metal and stone.; It wasn't a time when metal and stone were used together.

Past/Perfective
Negative
Polite
Terminal Form