Even China’s population will be declining by the early 2030s, according to the UN, which projects that by 2050 populations will be lower than they are today in 50 countries.
【核心词汇】
declining a.下滑的，衰退的
project v.表达，投射
according to根据
【结构分析】本句主干是Even China’s population will be declining by the early 2030s, according to the UN，其后的`which引导的定语从句which projects that by 2050 populations will be lower than they are today in 50 countries修饰先行词UN，关系代词在从句中作主语，注意这里project是动词，充当谓语，译为“指出”，后面的that引导宾语从句。
【参考译文】联合国有关报告指出，即便是中国，到2030年初期人口也将开始下降。这份报告还指出，到2050年，将有50个国家的人口低于今天的水平。