读下列古诗，答题。

                                                                                                         夜  雪
                                                                                                       唐·白居易
                                                                                             已讶衾枕冷，复见窗户明。
                                                                                             夜深知雪重，时闻折竹声。
    【注】：元和十三年，白居易因上书论宰相遇刺事被贬江州。