Staff Sergeant Richard Green, an 82nd Airborne Division mechanic, found this out first-hand when he accidentally damaged his unit's first M-ATV.

VOA: standard.2010.08.01

We have the convention of music of writing this symbol indicating the beat-carrying unit of four so I'm writing a four underneath each of these.

我们有一个约定俗成的书写格式,来表示四拍一单元,所以我在每行这里的下面写上一个四

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