硫化 りゅうか変色 へんしょくではありませんでした
ryūkahenshokudewārimasendeshita

Noun
Desu Copula

The polite, past negative form of 硫化変色

1. Was not sulfur discoloration.; Was not a change in sulfur coloration.

Past/Perfective
Negative
Polite
Formal Register