By 1970 DDT spraying, elimination of mosquito breeding sites and the expanded use of antimalarial drugs freed more than 500 million people, or roughly one third of those previously living under malaria's cloud.
By 1970 DDT spraying, elimination of mosquito breeding sites and the expanded use of antimalarial drugs freed more than 500 million people, or roughly one third of those previously living under malaria's cloud.
到了1970年，由于喷灑DDT、清除蚊子繁殖地，以及扩大使用抗疟药物，超过五亿人得以免受疟疾的威胁，约略是原先生活在疟疾阴影下人口的1/3。