阅读下面一首诗，完成题目。
                                                                                                                       宿云梦馆（欧阳修）
                                                                                                               北雁来时岁已昏，私书归梦杳难分。
                                                                                                               井桐叶落池荷尽，一夜西窗雨不闻。