使わなければいけない

have to use

→ 使う
phrase Rare #39,362
have to use Expresses obligation or necessity. Literally, it means that not using something would be unacceptable.
JA: この薬は毎日使わなければいけない。
EN: I have to use this medicine every day.

この望遠鏡は注意して使わなければいけない。

This telescope must be used with care.

ケーキを作るときには、卵、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.