阅读下面这首诗，完成后面小题。
                                                                                                   东栏梨花  

                                                                                                     宋·苏轼
                                                                              梨花淡白柳深青，柳絮飞时花满城。
                                                                              惆怅东栏一枝雪，人生看得几清明？
                                                                             注：①东栏：指诗人庭院门口的栏杆。