The old lady's class was indeed unique, her subject was the bronze ware of the Shang-Zhou period, and during the class, she also explained many types of bronze ware, some of which you had learned about, as well as some you had never heard of.
The script of the Shang Dynasty was Oracle Bone Script, so she deliberately spent a whole class explaining it. While she was lecturing on stage, you were translating the Oracle Bone Script in the black stone with the knowledge you had just absorbed.
Interestingly, there were a total of one hundred and twenty Oracle Bone Script characters in the black stone, but the ones listed by the old lady in the projector only covered ninety-nine percent of them. There were still about a dozen characters unexplained. And these dozen characters were precisely in the last sentence, playing a crucial role!