海中 かいちゅう展望 てんぼう だいじゃありませんでした
kaichūtembō daija arimasendeshita

Noun
Desu Copula

The polite, past negative form of 海中展望台

1. It wasn't an underwater observatory.; It wasn't the underwater observation deck.

Past/Perfective
Negative
Polite
Terminal Form