2. Yogurt is made from fresh milk and fermented with active lactic acid bacteria. Yogurt is rich in lactic acid bacteria and has proper acidity, which can prevent diarrhea. Drinking yogurt often can effectively inhibit the production of harmful bacteria and improve immunity.

3. Drinking pure milk is of great benefit to promote the growth of primary school students' teeth and bones. Pure milk is rich in protein and amino acids, as well as mineral components such as phosphorus, iron, zinc, copper, manganese and molybdenum, which are also necessary for children to grow up.