Different Dimension Ceiling

Wenwen couldn't sleep again at night. She lay on the small bed in her dormitory, tossing and turning, but couldn't fall asleep. "Hey, why is it this voice again? What the hell." Wenwen muttered in his heart. Wenwen slept on the upper bunk, very close to the ceiling, and the voice was also very close to Wenwen. What exactly is that sound? Did the ceiling tell Wenwen the answer? Please look forward to it~