阅读下文，回答相关问题。

                                                                                                                                              除夜作
                                                                                                                                                高适
                                                                                                                      旅馆寒灯独不眠， 客心何事转凄然？
                                                                                                                       故乡今夜思千里， 霜鬓明朝又一年。

—Yes, and most of them       __in the western part of China.

已知△ABC中，∠C=90°，AC=6，BC=8， 则cosB的值是

俄罗斯大部分地区冬季十分寒冷的主要原因是