地下鉄

How it works

A casual “let’s do it” invitation. に (to) marks 地下鉄(ちかてつ) (the subway) as the thing you board. The verb 乗る(のる) (ride) shifts to its volitional form 乗ろう(のろう) (let’s ride), which proposes doing something together — plain and friendly, no ましょう (let’s, polite) here.