Some cabinets were not locked. When Yu Fei suddenly opened a cabinet, a sharp and sharp sound suddenly sounded in the room.

"ah!"

The unsuspecting Zhu Yu was so frightened that she jumped up again and hung on Gu Hui.

"I seem to have found the reason!"

Yu Fei pointed to the cabinet he opened the door and said to the two of them.

To be honest, Gu Hui was startled by the sudden sound. He looked at Yu Fei when he heard Yu Fei speak. Zhu Yu turned her head tremblingly and looked over, before she got off Gu Hui.

Squeak! Squeak! Squeak!...

Yu Fei quickly opened and closed the door a few times, and then when he opened and closed it, a different sound came from the cabinet door.

This sound was somewhat similar to the sound they heard outside, but it seemed different.

"The source of the sound is the cabinet door. The bearing underneath is broken, so when it is opened and closed, the metal friction will make a sharp sound!"

"The locking device of the window over there is broken, so the wind outside the window is the source of power!"

"The reason why the sound we hear is different from this is because the sound reverberation has changed after being propagated by the ventilation duct and blocked by the door!"
Chapter completed!