可逆 かぎゃく変化 へんかではありませんでした
fuka gyakuhenkadewārimasendeshita

Noun
Desu Copula

The polite, past negative form of 不可逆変化

1. Was not an irreversible change.; Was not an unrecoverable alteration.

Past/Perfective
Negative
Polite
Formal Register