In 2000, the World Health Organization (WHO) announced that China was already a polio-free country.
2000年,世界卫生组织(WHO)宣布中国已成为一个没有脊髓灰质炎的国家。
The region is polio-free, and has been for ten years.
该区域已经有十年无脊髓灰质炎。
Its main task is to monitor the polio-free status of the region.
其主要任务是监测该区域的无脊髓灰质炎状况。
应用推荐