専門 せんもん分野 ぶんやではありませんでした
semmombun'yadewārimasendeshita

Noun
Desu Copula

The polite, past negative form of 専門分野

1. Was not my specialty.; Was not my field of expertise.; I was not familiar with it.

Past/Perfective
Negative
Polite
Formal Register