usc说我的成绩单不行，谁能帮我看看？

Thank you for your inquiry. We have reviewed your application for admission to graduate study, and
are unable to proceed because of important items or information missing from your file. These items
are listed below:
-***University: An official grading scale for your coursework. The documents
you sent us do not provide sufficient information concerning the scale by which your previous
educators evaluated your performance. The official grading scale must be sent directly from your
institution in a sealed envelope to the following address:

谁知道这是什么意思呀？

就是说成绩单要装在密封的信封里给学校。

肯定是成绩单没密封啦

没有密封

或者你按照一种算法把评分档寄送过去

我没搞明白,LZ你到底是密封了寄出去的还是没密封就寄了?