ちょう新星 しんせい爆発 ばくはつじゃなかったです
chōshin sei bakuhatsujanakattadesu

Noun
Desu Copula

The polite, past negative form of 超新星爆発

1. Wasn't a supernova.

Past/Perfective
Negative
Polite
Casual Register
Astronomy