C is a necessary technical feature. There is no C connecting A and B? It is inevitable that the technical scheme cannot be realized, so it is certain that C is indispensable;
2. As for you saying that C is represented by D, you also quoted that C can be realized by D and E, and even f g h, which is related to the problem that the claim can be properly summarized at the upper level and can be summarized by technicians in this field;
For example, exclusive rights: there is an x, which is characterized by a and b connected by metal c; No problem, because your instructions may give multiple examples to support C as gold, silver, copper, iron and aluminum. . . . And as long as it is metal, the exclusive right can be directly summarized as C is "metal"; Then the affiliation can be restricted separately;
3. So the problem can be summed up properly. In the above example, metals can be completely summarized; Sometimes you can't. Look at the specific case, from the perspective of ordinary technicians in this field. For example, C may require a high melting point of metals, so it cannot be directly summarized as all metals, and must be limited to metals with a melting point exceeding XX. Then, define it from the right.
I hope I can help you.