存款证明的疑惑

钰剑乘风UID：3279007

收到学校邮件说要寄存款证明。
描述是这样的：
The Confidential Bank Statement must be on official bank letterhead, dated within one year of your planned enrollment, signed or stamped by a bank official, and cover the estimated cost of educational and living expenses for one year of study for your program. The account holder's name must be translated into English and be the same as the name listed on the Affidavit of Support Form.

我想问这个资金要冻结到什么时候呢？上面貌似没有要求哇。。。。