じゅう ぷん きに運転 うんてんじゃなかったです
jūpun'okini untenjanakattadesu

Noun
Desu Copula

The polite, past negative form of 十分置きに運転

1. Wasn't driven every ten minutes.; Wasn't operated every ten minutes.

Past/Perfective
Negative
Polite
Casual Register