Please keep a duplicate of the signed contract in the legal department's files.

請將已簽署合約的副本存放在法務部的檔案中。

The hotel front desk issued me a duplicate when I lost my room key.

我弄丟房卡後，飯店櫃檯補發了一張備用卡給我。

Our system flagged the invoice as a duplicate, so the payment was not processed twice.

我們的系統將這張發票標記為重複項目，所以款項沒有被付兩次。