Section4:immune, flu, medicine,children, sand, irrigation, organic, weeds, roots, water,nutrition
小作文：:线图, health、education、roads and railways从2000到2025国家GDP消费比例的变化
大作文：social networking sites have a huge impact on both individual and society,to what extent do you agree or disagree?
大作文:The users of social media, such as Facebook, Twitter, are replacing face-to-face contact in this century. Do you think the advantages of this way outweigh the disadvantages?