こう性能 せいのう爆薬 ばくやくじゃありませんでした
kōseinō baku yakuja arimasendeshita

Noun
Desu Copula

The polite, past negative form of 高性能爆薬

1. It was not a high-performance explosive.; It wasn't a high-performance explosive.

Past/Perfective
Negative
Polite
Terminal Form