26．（15分）⑴                          ；

⑵                                                   。

反应类型是                         。

⑶                                          。

⑷                                、

                                               。

⑸           

27．（15分）

⑴                                  

⑵                                  

⑶                                   

⑷                                    ⑸                                  。

⑹                                                      。                 

28．（15分）

⑴                               

⑵                               

①                             。

②                                                 

                                                          。

⑵①                                            。