阅读下面古诗。
                                                                                                          商山早行
                                                                                                             温庭筠
                                                                                             晨起动征铎，客行悲故乡。
                                                                                             鸡声茅店月，人迹板桥霜。
                                                                                             槲叶落山路，枳花照驿墙。
                                                                                             因思杜陵梦，凫雁满回塘。