Let's give a simpler example. After careful comparison and research, after considering the performance and actual needs, I made a list of all the parts of a computer, and then I saved a computer. I made a case myself, and I made a slot in it. Other cpu, memory and other parts are bought by brands such as Intel and Kingston. I have "completely independent intellectual property rights" for this computer. Of course, this metaphor is not appropriate, because designing an airplane is very complicated and there are quite a few technical problems to consider. Therefore, although the core components are all purchased from foreign companies, it is no small achievement for China Aircraft Industry to design a commercial single-aisle aircraft. Exaggerating "independent intellectual property rights" is a bit boastful, but there is no need to sell yourself short. China's industry is going through the most difficult process from quantitative change to qualitative change, with a long way to go. The independent design of C9 19 is only a starting point.