在售货方开出订购单收据之后， 售货方必须在三天之内，在返回的订购单的副本签字，并把这个副本邮寄给购买方，这样做才能确认这个订购单。

This Purchase order shall be confirmed by Seller's signing on the returning copy of this Purchase Order and mailing the copy to Buyer within three days after Seller's receipt of this Purchase Order.

youdao

在售货方开出订购单收据之后， 售货方必须在三天之内，在返回的订购单的副本签字，并把这个副本邮寄给购买方，这样做才能确认这个订购单。

This Purchase order shall be confirmed by Seller's signing on the returning copy of this Purchase Order and mailing the copy to Buyer within three days after Seller's receipt of this Purchase Order.

youdao