炭酸 たんさんマグネシウムじゃありませんでした
tansammaguneshiumujārimasendeshita

Noun
Desu Copula

The polite, past negative form of 炭酸マグネシウム

1. Was not magnesium carbonate.; Wasn't magnesium carbonate.

Past/Perfective
Negative
Polite
Terminal Form