C40 Ruler Event

In this math class, Liu Lei saw Li Xiaomei had an extra ruler, and he himself also had a ruler. But after thinking for a bit, he put the ruler in the drawer, and then deliberately said: "Aiya! I forgot to bring a ruler! " Liu Lei's voice was quite loud. Of course, he had a purpose. With that said, what happened next would naturally follow.

Jim had seen everything Liu Lei had done