When I was young, I idolized Sherlock Holmes and had the idea of "becoming a Sherlock Holmes". It took me many years to find it impossible, no matter how hard I tried-because I couldn't accumulate the knowledge I needed. The difficulty of being a Sherlock Holmes in reality is that you need amazing knowledge reserve and retrieval ability. In fact, you must become a self-propelled library or a large digital storage medium with astronomical figures. In other words, it is not impossible to make a deductive observation like the original text, but the difficulty lies in whether your database is large enough, not whether there are enough search conditions.