The sound in the staff library is loud and quiet.

Does the questioner want to ask "Why is the sound in the staff library suddenly louder and softer?" People move around and noise interferes.

1. Movement of people: The movement of people in the employee library causes the sound to be louder and quieter. Employees can be reminded to keep quiet, or slogans can be set up in the library to remind employees to pay attention to the sound level.

2. Noise interference: There is noise interference around the employee study room, such as voices in other rooms, air conditioning, etc. You can try to contact the relevant departments to reduce noise interference.