藏文史籍《萨迦世系表》载：“元帝辖十一省，西藏之地面积虽不足一省，但因为它是八思巴的住地和教法所以，故作为一省委付与八思巴。”元代实行行省制度，负责管理西藏省的中央机构是

阅读《钱塘湖春行》回答下面的问题。

                                                                                                                                 钱塘湖春行

                                                                                                                                唐  白居易

                                                                                                            孤山寺北贾亭西，水面初平云脚低。

                                                                                                           几处早莺争暖树，谁家新燕啄春泥。

                                                                                                           乱花渐欲迷人眼，浅草才能没马蹄。

                                                                                                           最爱湖东行不足，绿杨阴里白沙堤。