从结构层次上看，下列哪项与其他三项不同（  ）

阅读《最美人瑞这样走来》一文，回答下列各题。

最美人瑞这样走来

    ①早在做同事之前，在东四头条的社科院宿舍大院，我和杨绛先生就做过邻居，按“翰林院”（中国社会科学院）不成文的规矩，作为小字辈的我，要按其本名，尊称她“季康先生”。

    ②初见时，季康先生年过半百。精瘦娇小，举止文静轻柔，但整个人极有精神，特别是两道遒劲高挑而又急骤下折的弯眉，显示出一种坚毅刚强的性格。她的衣着从来都整齐利索，即使在家不意碰见来访者敲门的时候。她始终保持着西洋妇女那种特定的“尊重自己，也尊重别人”的习惯。

    ③在公共场合，季康先生从来都是低姿态的，她脸上总是挂着一丝谦逊的微笑。她总是把自己的语言压缩到最少。

    ④在我见到的大家名流中，钱、杨二位先生要算是最为平实，甚至最为谦逊的两位，季康先生虽然有时穿得雍容华贵，神情态度却平和得像邻里阿姨。

    ⑤但这个看似低调谦恭的阿姨，也有吃了熊心豹子胆的时候，且这个时候出现得无比不合时宜。“文革”之初，他们被造反派揪出来，挂了牌子押上批斗会。可杨季康对“天兵天将”的推推搡搡公然进行了反抗，而且怒目而视。要知道，不少老战士都没有一个敢于如此维护自己被践踏了的尊严的。

    ⑥“文革”后期，钱、杨二位先生尚未获得平反，有家回不了，四处流转。但对于这群甚至未能为他们说句公道话的晚辈，他们以极高的涵养、含蓄内敛且从不显于言辞的方式予以理解、宽容和无私帮助。

    ⑦有一次，我家因额外开支经济上一时告急，杨先生得知后主动支援了我们几百元钱。以后每月都资助我二十元人民币。后来我还获知，研究所里每月不落地从先生那里得到接济的竟有十多个像我们这样的年轻人，且持续了好几年。经历了人生的磨难，却能如此悲悯，如此退让，如此宽厚慈祥，如此菩萨心肠，这是我在“翰林院”所见到的唯一一例。

    ⑧先生施恩于后辈，大部分无法用金钱计算。20世纪80年代初，我访法归来写的两本书准备出版，因考虑到之前有前辈权威的横眉冷对，我特地在前言中恭敬写明“抛砖引玉”。当然，敬赠给钱、杨二位先生，抱的心态自然不同。很快，杨先生回信了，还是一贯的低调谦恭与幽默：“假如你抛出一块小砖，肯定会引来大堆的砖头瓦片，但是珠玉在前，砖就不敢出来了……天气酷热，多多保重……杨绛八月十三日钟书同候。”

    ⑨先生过百岁大寿时，深知先生君子之道的我，自然不敢上门叼扰。当电话里听到老太太爽朗清晰的声音时，我仿佛又回到了三十年前的那个夏天，依然如喝了冰水那样舒心畅快﹣﹣只是多少也有几分伤感，因为不可能有“钟书同候”了。

（选文有改动）

【注释】①人瑞，常指百岁以上德高望重的人。

如图，△ABC中，D、E分别在边AB、AC上，CD平分∠ACB，DE∥BC，如果AC=10，BC=15，那么AE=____ ．

根据短文理解，选择正确答案。

    At thirteen, I was diagnosed（诊断） with kind of attention disorder. It made school difficult for me. When everyone else in the class was focusing on tasks, I could not.

    In my first literature class, Mrs. Smith asked us to read a story and then write on it, all within 45 minutes. I raised my hand right away and said, “Mrs. Smith, you see, the doctor said I have attention problems. I might not be able to do it.”

    She glanced down at me through her glasses, “You are not different from your classmates, young man.”

    I tried, but I didn't finish the reading when the bell rang. I had to take it home. In the quietness of my bedroom, the story suddenly all became clear to me. It was about a blind person, Louis Braille. He lived in a time when the blind couldn't get much education. But Louis didn't give up. Instead, he invented a reading system of raised dots（点）, which opened up a whole new world of knowledge to the blind.

    Wasn't I the “blind” in my class, being made to learn like the “sighted” students? My thoughts spilled out and my pen started to dance. I completed the task within 40 minutes. Indeed, I was no different from others; I just needed a quieter place. If Louis could find his way out of his problems, why should I ever give up?

    I didn't expect anything when I handled in my paper to Mrs. Smith, so it was quite a surprise when it came back to me the next day- with an “A” on it. At the bottom of the paper were these words: “See what you can do when you keep trying?”