In the A, B, C, D and F grading system, the first four letters are typically considered passing grades.

在 A、B、C、D 和 F 评分体系中，前四个字母通常被认为是及格。

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Figure 3: Performance TAB shows you a letter grade (a, b, c, d, f) and a percent grade (1-100).

图3：性能标签使用字母(A, B, C, D, F)表示等级以及当前等级(1 - 100)。

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CrashMetrics ticks all the important boxes: a accuracy, b correct level of mathematics, c understandability, d robustness, e flexibility, f ease of use.

CrashMetrics符合下列一切要求：a准确，b正确的量化程度，c易理解，d稳定，e灵活，f易用。

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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

These between B and C and E and F didn't get filled in because they were already just the smallest amount that they wanted to deal with, just half steps.

但是B和C,E和F之间并没有被填上,因为它们之间已经是最小的距离,只是个半音级,人们愿意摆弄的最小距离

耶鲁公开课 - 聆听音乐课程节选

Highlights include the Air Force Flight Test Center Museum, the food court and gift shop at the NASA Dryden Flight Research Center and a "windshield tour" near the flight line where F-16s, KC-135s, F-22s, F-35s, B-1s or C-17s might be visible, said the spokesman.

CNN: Where planes go to die