1. A bar is a regular segment in the music score. The purpose of dividing the bar is to facilitate reading and counting.

2. Let’s talk about the time signature, 4/4,?①(Part 4 ) means that a quarter note is 1 beat? ② (upper 4) means 4 beats in a measure.

The total length of the notes in the measure is determined by the time signature on the score.

3.③ is the note, which records the duration (length) and pitch of the note