下面是发票，一旦有空帮忙开发票的翻译：Here is the invoice, once a blank help invoicing 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

Here is the invoice, invoice, once free help

Here is the invoice, once a blank help invoicing

Below is a receipt, once has free time helps to write the receipt

The following are some vacant help billing invoices, once

Here is the invoice, once a blank help invoicing