诗歌前两句写景的角度不同，上句是____，下句是____，上下交映，突出了大漠和月色的白光一片，寒气侵人，描绘了边地的 ____。

                                                                                                      登岳阳楼
                                                                                          昔闻洞庭水，今上岳阳楼。
                                                                                          吴楚东南坼，乾坤日夜浮。
                                                                                          亲朋无一字，老病有孤舟。
                                                                                          戎马关山北，凭轩涕泗流。