仮定 かてい ほう過去 かこ完了 かんりょうでしょう
kateihōka kokanryōdeshō

Noun
Desu Copula

Expresses probability in a polite manner ("probably…") of 仮定法過去完了

1. Would have been; Might have been

Polite
Presumptive
Conjecture
Linguistics