规定时间内(通常是夜里)不许随意使用灯、火这类发光发亮的东西      主要目的是为了防空，避免从空中发现地面目标      BlackoutandAll Clearare the two volumes that comprise a2010science fictionnovel by AmericanauthorConnie Willis      Blackoutwas published February 2, 2010 bySpectra       The second part, the conclusionAll Clear, was released as a separate book on October 19, 2010      Thediptychwon the 2010Nebula Award for Best Novel,the 2011Locus Award for Best Science Fiction Novel,and the 2011Hugo Award for Best Novel      These two volumes are the most recent of four books and a short story that Willis has written involvingtime travelfromOxfordduring the mid 21st century