It was a hot summer when I was in the second grade of primary school. After dinner, I went downstairs to play with my good friend Liu Xu. We play in the corridor. I found many small advertisements posted on the corridor door. Liu Xu and I discussed whether we should clean up the small advertisements in the corridor. Liu Xu agreed. So, we started to cooperate.

We both work together. Liu Xu sprinkles water from their house, and I row with a knife. We began to work. The knife is paddling in my hand, but the small advertisement still doesn't work. It seems to be against us. Liu Xu had a good idea. Tell me, don't worry. After the advertisement was soaked in water, you paddled hard, and I did as he said. It really works, that's all. It's not easy to clean up small advertisements! There are many mosquitoes in summer, and many big bags are nailed to Liu Xu's head, legs and arms. We don't feel tired at all and we work very hard. It was already past nine o'clock in the evening. We spent two hours cleaning both sides of the glass.

Looking at the fruits of our labor, Liu Xu and I were both beaming.