名词解释:自2015年8月20日启动中国人民抗日战争暨世界反法西斯战争胜利70周年纪念活动空气质量保障措施以来，机动车限行、企业停限产、工地停工等减排措施落实到位，再加上周边部分省市也提前启动保障措施，使得北京的空气质量持续优良，pm2.5浓度水平创有观测记录以来连续5日浓度最低值。继“APEC蓝”后，“阅兵蓝”成为首都新目标。你知道怎么用英语表达吗?

According to a report by the environment protection authority, Beijing's PM2.5 index has remained excellent since Aug 20, and the media has called the blue sky in Beijing during this period "parade blue".

During the rehearsal and the parade, Chairman Mao Memorial Hall and the Palace Museum are closed to the public.

Besides traffic controls, eighty percent of the vehicles used by government bureaus and institutes have been banned from use, and construction sites that generate dust have been asked to shut down.

北京市环保局的一份报告显示，自8月20日起，北京PM2.5浓度连续保持一级优，媒体称这段时间的蓝天为“阅兵蓝”。

在阅兵演练和正式阅兵期间，毛主席纪念堂和故宫暂停对公众开放。

除了交通管制，80%的公车停驶，一些产生扬尘的建筑工地也被关停。

【讲解】

文中的parade blue就是“阅兵蓝”的意思，“阅兵蓝”的说法源于去年11月初的“APEC蓝”(APEC blue)，由于采取了一系列减排措施，包括周边城市工厂停产(suspend production by factories in neighboring cities)，限制演练区域的交通流(traffic flow)等，北京出现了蓝天白云。

最后一句中的shut down是动词短语，表示“(使工厂、公司等)关闭，歇业，停业”，如：Smaller contractors have been forced to shut down.(规模较小的承包商已被迫歇业。)