阅读下面的诗歌 ，回答相关问题
                                                                                                     渡荆门送别
                                                                                                           李白
                                                                                         渡远荆门外，来从楚国游。
                                                                                         山随平野尽，江入大荒流。
                                                                                         月下飞天镜，云生结海楼。
                                                                                         仍怜故乡水，万里送行舟。

将带花的白玉兰枝条插入稀释的红墨水中，一段时间后花瓣变成红色．与这一现象直接相关的组织是（　　）

Once there lived an old man in a town. He always forgot a lot of things. So his wife always had to say to him，“Don’t forget this.”
One day he went on a long way alone. Before he left home，his wife said，“Now you have all these things. You need them on your way. Take care of your things on the way.” He went to the station. He bought a ticket and got on the train with it.
About an hour later，the conductor began to see the tickets. He came to the old man and said，“Will you please show me your ticket?” The old man looked for his ticket in all his pockets but he could not find it. He was very worried.“I can’t find my ticket. I really bought a ticket before I got on the train ”said the old man.
“I think you are right. I believe you bought a ticket. All right，you don’t have to buy another ticket ”said the conductor kindly. But the old man still(仍然) looked worried and said sadly，“You don’t know why I’m worried. If I don’t find my ticket，I can’t remember my station. Where am I going? ”

历史发展一般都具有阶段性特征。辽、宋、西夏、金时期最显著的阶段特征是（    ）