求翻译：9月7日，上海计划年内将确保率先完成中心城区50万NGB建设，发展25万高清电视用户；在未来三年内完成500万户下一代广播电视网（NGB）建设．是什么意思？

September 7, Shanghai plans to complete the first year will ensure that 500,000 NGB building downtown, the development of 250,000 high-definition TV users; in the next three years to complete five million next-generation broadcast networks (NGB) construction.

On 7 September, the Shanghai plans will ensure that lead to complete the downtown areas 250,000 500,000 NGB building development, high-definition TV users; in the next 3 years to complete 5 million households next generation Radio and Television Network (NGB building).

On September 7, in the Shanghai plan year will guarantee takes the lead to complete the central city 500,000 NGB constructions, will develop 250,000 high clear television users; Will complete 5,000,000 household next generation broadcast television network (NGB) construction in the future three year

On September 7, 500,000 NGB plans will ensure that the first to complete in the year central city building, development of 250,000 HDTV user; completed 5 million within the next three years the next generation of radio and television network (NGB) building.

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