should 本应该做某事却没有做,表示责备和遗憾. 如; You should ahve told me the news eariler. would 表示与事实相反。 1。If I were a bird, I would be happy.(与现在事实相反) 2. If I had told him the news, he would have cried..(与过去事实相反) 3. If I were to go tomorrow, I would take a plane..(与将来事实相反)