refers to the 4/4 beat, which is just another idiom. 4/2 beats are marked with CC.

the mark of the whole note is c, let c be equal to 1, and the duration of the binary note is naturally 1/2. When there are two beats (two binary notes) in a bar, the duration is 1/2+1/2, and the time signature in fractional form is 2/2. When there are three beats (three binary notes) in a bar, the duration is 1/2+1/2+1/2, and the time signature in fractional form is 3/2.

when the treble clef is used, it is also called the g clef, and the central C(dol) is added with a line below. The second line, that is, the line from which the pen starts when drawing a treble clef, specifies the pitch as G(sol). When using the bass clef, it means that the four lines of the staff are F, also known as the F clef, and the top line indicates the central C. Extended data

Music is always alternated by strong beats and weak beats. This alternation can't be arranged randomly, but a bar is organized according to a certain law to form the minimum beat, and then it is cycled back and forth. For example, when there is only one weak beat between two strong beats, it is called "double beat", and 2/4 beat is this type;

when there are two weak beats between two strong beats, it is called triple beat, like 3/4 and 3/8; There are three weak beats between two strong beats called "four beats", and the common one is 4/4. The two bars are separated by a bar line. The section line is a thin line perpendicular to the spectrum table, with five lines at the top and one line at the bottom, which just cuts off the spectrum table. No matter how far the upper and lower lines are from the spectrum table, the section line cannot go beyond the spectrum table.

Two bar lines are drawn in the last bar of the work, and the one on the right is thicker, indicating the end of a work or a paragraph. The beat behind the bar line must be a strong beat, and there is only one strong beat in each bar, and the rest are weak beats.

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