BEIJING - China will build a nation-wide network within three to five years to monitor the impact of air pollution on health, a latest step to deal with a persistent smog crisis in big cities, an official said. A total of 43 monitoring spots will be set up in 16 provinces and municipalities frequently engulfed by smog so as to facilitate research on air pollutants in different regions, the impact on the health of vulnerable groups and the study of related diseases, said Xu Dongqun, an official with the Chinese Center for Disease Control and Prevention. With funds allocated by the central government, the study will provide reference for preventive efforts to reduce the PM 2.5, Xu said. Thick and dangerous smog have hit 17 provinces and municipalities with a population of 600 million this year. One of the major cities is Beijing, which has been shrouded in smog for several days during the ongoing seven-day national holiday in 2013. China recently issued a 1.75 trillion-yuan (284.2 billion U.S. dollars) plan to deal with the worsening air, improving air quality within five years in order to decrease the number of heavily polluted days and improve the air in major city clusters. 小题1: China will build a nation-wide network in order to_________. A．monitor the impact of air pollution on health B．improve air quality C．improve air pollution D．increase the PM 2.5 小题2:The underlined word “ persistent ” means“________”. A．短时的 B．持久的 C．短暂的 D．停留的 小题3: China will take measures to deal with air pollution except________. A．China recently issued a 1.75 trillion-yuan (284.2 billion U.S. dollars) plan B．set up monitoring spots in 16 provinces and municipalities C．improveliving standard D．improve the air in major city clusters 小题4: We can infer from the paragraph________. A．Thick and dangerous smog have hit 17 provinces and municipalities B．air pollution impacted a population of 600 million this year C．The people in Beijing probably wore masks when they walked on the street during the national holiday in 2013. D．the study will provide reference for preventive efforts to reduce the PM 2.5