Most American colleges and universities use the grading system of A,B,C,D and F.

VOA: special.2009.03.05

So they began to call this A and this B and this C and this D and this E, this F, this G.

他们开始把这叫做A,B和C,这个是D,E,F,G

耶鲁公开课 - 聆听音乐课程节选

I personally don't like swings that much and it's the B-/B+ range, so I'd much rather prefer that to a swing from A to C, and that's my reason.

我不喜欢成绩波动很大的,比如B-/B+这个范围,所以我还是喜欢像A到C这样小点的,这就是我的原因

耶鲁公开课 - 博弈论课程节选

They are known as vitamins A, the B group,C,D,E and K.

VOA: special.2009.04.21