For generations, scientists and science-fiction writers talked about the similarity of Mars to Earth.一代代的科学家和科幻小说作家都讲到了火星与地球的相似之处。I've always been a closet science-fiction fan.我私下里一直是个科幻小说迷。The average reader of science-fiction is young and male.科幻小说的读者一般都是年轻的男性。