刚收到USC的邮件,说已经academically eligible for admission,不过需要交一份类似的证明, 'If your studies are being privately financed, in whole or in part, you must submit both a bank letter and a letter from your sponsor (if not yourself) promising support for one year.',问问各位被USC录取的同学这个东西是什么啊?该怎么出?