我在一大公司做R&D工作。公司递交了EB1B的I140。人事部写了一封EMPLOYMENT VERIFICATION LETTER，注明我是FULL TIME，原话是“At this time we wish to confirm that our offer of full-time employment is still available to him”，并写了TITLE和工资。
现在收到USCIS的RFE LETTER，要求“Please submit a complete copy of the actual letter and/or contract offering employment to the beneficiary issued by the appropriate hiring authority. This letter must be addressed to the beneficiary, and must have been written prior to the filing of the petition. The letter or contract must set forth the title, terms and conditions of the position and be from a department, division, or institute of a private employer offering the beneficiary a permanent research position in the beneficiary’s academic field”。律师准备把我入公司时签字的OFFER LETTER递交上去。
请问USCIS要求的是这封信吗？还需要补充什么材料吗？
为什么USCIS要求“a complete copy of the actual letter and/or contract offering employment”？是不是因为EMPLOYMENT VERIFICATION LETTER里那句“we wish to confirm that our offer of full-time employment is still available to him”很模糊，所以USCIS想看“actual letter and/or contract offering employment”。
请各位大师指点。