Because the British began to use the note name, and Irish music has many minor keys, and the tonic is la, so they gave the note name A to la (ABCDEFG), so that do became C.

The main source of modern music is German and Austrian classical music. They are popular in major keys, and do is the main tone, ranking first. The note names in modern music are arranged in major keys, so the first note becomes C, and ABCDEFG, which originated in the UK, became CDEFGAB, the most commonly used note in the world.

Extended information

The seven basic tone levels are repeated repeatedly to form the entire musical sequence. The sequence of notes starting from C to C, an octave higher, is called a group. A group of sounds usually starting from the C sound in the second space of the bass clef, marked with lowercase Latin letters c, d, e, f, g, a, b, is called a small character group, and each group upwards is called One group of small characters, two groups of small characters, etc.

The groups going down are marked with capital Latin letters in turn, and are called large character group, large character group one, large character group two, etc. The small c in the group is located on the central plus line of the large staff, so it is called middle C; it is also located in the center on the keyboard.

In addition, there are also those with middle C as the small group; the musical instrument manufacturing industry uses the numerical sequence of piano keys as the standard; the American Standards Association, based on the initiative of the Acoustical Society, uses the three octaves below middle C The C sound is the beginning of the first group, labeled C1, and then proceeds to C7, which is now commonly used in the Western acoustic community.