ちょう新星 しんせい爆発 ばくはつじゃありませんでした
chōshin sei bakuhatsujārimasendeshita

Noun
Desu Copula

The polite, past negative form of 超新星爆発

1. It wasn't a supernova.

Past/Perfective
Negative
Polite
Terminal Form
Astronomy