blessing
1.blessing和bliss意思相仿，但blessing是类名词，bliss是抽象名词。例如：What a blessing it is to live and work in this city!（必须有a）和What bliss it is to live and work in this city!（不可有a）
2.说“不幸中的大幸”只可用blessing，不可用bliss，如What a blessing it is that you were only slightly hurt in the accident里的a blessing不可改作bliss。
