Suny Buffalo网申的成绩换算，谢谢！

网申SUNY buffalo的时候碰到一个问题：需要将课程的分数换算成A,B,C等级，原话是这样子的：

”List ALL college courses you have or are now taking within the categories listed below. Record your grades as A, B, C, D, or F using +/- as appropriate, e.g. B+, A-, etc.
If your institution(s) used a different grading system, apply the conversion they stipulate or a standard conversion, IF POSSIBLE.“

我们学校的等级是这样子划分的，A--95；B-85；C-75；但是我有些课是87,89,91之类的分数，这些分数该用什么表示了？A还是B了？还是自己弄个A-，B+？希望有经验的同学指导下。谢谢！