放射 ほうしゃ せい系列 けいれつじゃなかったです
hōshaseikeiretsujanakattadesu

Noun
Desu Copula

The polite, past negative form of 放射性系列

1. Wasn't radioactive series.; Wasn't a radioactive series.

Past/Perfective
Negative
Polite
Casual Register
Physics