What is an Importer Security Filing (ISF)?  What is the marks and numbers field in the shipping instructions? What is the role of the shipper and the consignee in a bill of lading? What is the shipping instructions deadline?  What will be the consequences if the Import Security Filing is not completed on time?  When do I need to submit the Importer Security Filing?  Who needs a bill of lading? Why are there 3 original bills of lading? 什么是海运单？ 什么是装运须知？ 何时能收到核对副本？ 何时能获得正本提单（OBL）？