A phrase meaning that something is inevitable and will happen sooner or later — it's only a question of time.
この計画が実現するのは時間の問題だ。
It's only a matter of time before this plan comes to fruition.
彼の復帰は時間の問題にすぎない。
His return is merely a matter of time.
技術の進歩を考えれば、完全自動運転も時間の問題だ。
Given technological progress, fully autonomous driving is only a matter of time.