Dear friend, according to the information you provided, I'm not sure which character or story you are referring to. If you can provide more background or relevant information, I may be able to answer your question better. However, I can tell you something I know.

First of all, Archimedes was an ancient Greek scientist and inventor, and his contributions included buoyancy principle, lever principle, screw crane and so on. It has nothing to do with cherishing.

Secondly, a witness refers to a person who gives testimony in court or other legal proceedings. An agent is a person who works in secret or investigation in a government or private institution. These two professions are not directly related to cherishing.

Finally, if you mean Zhen Ai in a particular character or story, I need more information to provide you with a more accurate answer.