Problem description:

As a question, thank you for your suggestions!

Analysis:

Do you know the Second People's Hospital of Taiyuan (on Fuxi Street)? There is a crossroads to the east of the hospital. When you walk in, there is a shop dedicated to eliminating the four pests (it's close to Lei Yu Kindergarten in Taiyuan, and it's easier to find if you can find a kindergarten. Ask around, everyone knows). There is chalk to kill cockroaches. It is very useful to draw pictures in places where cockroaches haunt. That's how I get rid of cockroaches in my house. I tried many methods, but in the end this one worked. But sometimes the shop doesn't open, as if it didn't open until morning. I don't know why it's closed on Saturday and Sunday.