に役立つ

be useful for; help with

→ に
phrase Uncommon #8,394
be useful for; help with Used to say that something is useful for a person, purpose, or activity. The exact form に役立つ is the plain nonpast form; polite speech uses に役立ちます.
JA: 石けんは泥を落とすのに役立つ。
EN: Soap is useful for removing dirt.

石油はたいへん私たちの生活に役立つ

Oil is extremely useful in our daily lives.

演技に役立つ

It'll help with your acting.

— ラスト、コーション (2007)

相互理解平和に役立つ

Mutual understanding contributes to peace.

私もあげるものがこれを隠喩の勉強に役立つラジオ

Is this the radio I’m giving you as well, the one that will help you study metaphors?

— イル・ポスティーノ (1994)

ここいうに役立つ奴らだ

They're the kind of guys who come in handy when it really counts.

— ロード・オブ・ザ・リング/王の帰還 (2003)

この本は君の勉強に役立つだろう

This book will probably help you with your studies.

これはあなたの減量に役立つ良い運動です

This is a good exercise to help you lose weight.

世界平和に役立つために何をすべきだと思いますか

What do you think we should do to help promote world peace?

自分に役立つときだけ親切なんだよ

They're only kind when it benefits them.

— イル・ポスティーノ (1994)

私はこの条約世界の平和に役立つことを望んでいます

I hope this treaty will contribute to world peace.

法律を学ぶこと執行に役立つ考えていた警察弁護士任務を混同していた

I thought studying law would help with law enforcement, and I had confused the duties of the police and lawyers.

— エリート・スクワッド (2007)