以下是一封催证函正文部份，但顺序错乱，请选择正确的排序： ①The shipment date is approaching. We wish to remind you to open the L/C so that the shipment can be effected within the stipulated time. ②We hope to receive your draft L/C within the next week in order to avoid the delay of shipment. ③In order to avoid subsequent amendments and delay in shipment, please see to it that the L/C stipulations are in exact accordance with the terms of the PO. ④With reference to PO No. 123