C664 Guo Yuxin be Careful!

Guo Yuxin settled herself quietly next to Tang Haodong, careful not to interrupt his concentration. Her every move was feather-light, and she scarcely allowed herself to breathe too loudly. From 1:00 AM straight through to 5:00 AM, Tang Haodong had devoured the collection of thermodynamics books that Guo Yuxin had gathered. By now, his grasp of the subject was profoundly deep