[求助]正则表达式截取字符串
我有这样一个字符串：
***适用规定***                                                                  
2、适用范围：XXXXX。                                                       
3、适用客票：BSP ET票/本票ET票/B2B ET票。                                       
4、签    转、OPEN  票、RQ票：不允许。                                           
5、改期：不允许。                                                               
6、客票需按顺序使用。                                                           
7、退票：                                                                       
（1）自愿退票：                                                                 
？客票完全未使用：扣除50%退票费。                                               
？客票已部分使用：需补齐已使用航段Y舱公布运价。                                 
（2）非自愿退票                                                                 
？客票全部未使用：不收取退票费。