Many years later, Chu Yunping still had a copy of "Aerodynamics" on his bookshelf.
Juanxiu's handwriting on the title page reads:
The reasons why large passenger aircraft choose stratospheric movement are: high visibility, stable force, low noise pollution, and high safety factor.
Chu Yunping thought of Zuo Ling's smile or silence, and felt that she was the stratosphere that could make him fly.
Conception: