こう機能 きのう携帯 けいたい電話 でんわだったら
kō kinō keitaidenwadattara

Noun
Da Copula

The "-tara" conditional form ("if/when…") of 高機能携帯電話

1. If/when (it) was a high-spec mobile phone; If (it) were a high-spec mobile phone

Tara Conditional