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

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"The fact that some airlines have received A's and B's and others D's and F's on this report card also shows that providing decent customer service and avoidance of strandings is both achievable and should not place an undue burden on the airline industry or lead to higher ticket prices, " the report's executive summary said.

CNN: Delta one of top airlines to get an 'F' in report

For the Hedged Equity Fund, portfolio managers will take long positions--the outright purchase of equities--primarily in stocks that have ratings of A or B and short positions primarily in stocks that have ratings of D or F.

FORBES: Boomers Leap Into Financial Safety Net