Cách sử dụng
"In duplicate" means to create or make a second copy of something. It is often used in official or legal documents where multiple copies need to be made for record-keeping or documentation purposes. For example, if you need to send an important letter to someone, you may be required to send it "in duplicate," meaning you will need to make two copies of the letter and send both of them. This ensures that both you and the recipient have a copy of the document for reference or proof of receipt.