使わなければいけない

must use

→ 使う
phrase Rare #36,507
must use A common way to say “must use” or “have to use.” Literally, it means “if [someone] does not use [it], it will not do.”
JA: この道具を使わなければいけない。
EN: You must use this tool.

ケーキを作るときにはバター砂糖を使わなければいけない

When making a cake, you have to use eggs, butter, and sugar.

この望遠鏡注意して使わなければいけない

This telescope must be used with care.

予約を取るために彼女の名前を使わなければいけない

To make a reservation, I have to use her name.