You Did More Than Carry My books

    Mark was walking home from school one day when he noticed the boy ahead of him had dropped all of the books he was carrying, along with a baseball bat and several other things. Mark 1down and helped the boy pick up these articles. 2 they were going the same way, he helped to carry some of them for him. As they walked Mark 3 the boy's name was Bill, that he 4 computer games, baseball and history, that he was having a lot of 5  with his other subjects and that he had just broken 6 with his girlfriend.

    They arrived at Bill's home first and Mark was 7 in for a Coke and to watch some television. The afternoon passed 8 with a few laughs and some shared small talk, and then Mark went home. They 9to see each other around school, had lunch together once or twice, and then both ended up from the same high school. Just three weeks before 10 , Bill asked Mark if they 11 talk.

    Bill 12 him of the day years ago when they had first met. “Do you 13wonder why I was carrying so many things home that day?” asked Bill. “You see, I 14 out my locker because I didn't want to leave a mess(脏乱)15anyone else. I had planned to run away and I was going home to 16 my things. But after we spent some time together 17 and laughing, I realized that 18 I had done that, I would have19 a new friend and missed all the fun we would have together. So you see, Mark, when you picked up my books that day, you did a lot more. You 20 my life.”

 下列现象中，物体的运动状态没有发生变化的是(       )

伦敦上空的“鸽子空气巡警”

    ①英国伦敦一直有着“雾都”的别称，被称为这个星球上最毒的城市。英国人为摘“雾都”的帽子，多少年来一直在矢志不渝地努力治理空气污染。

    ②世界各地的雾霾治理中，对空气质量的实时检测一直是相当重要的工作。有的城市募集志愿者，携带空气质量检测仪，在城市中行走来搜集空气的数据。随着科技的发展，一些城市开始用无人机来监控，可以得到比较详细的数据。不过，英国伦敦想出了新的更好的办法。

    ③2016年3月16日，眼尖的伦敦市民突然发现自己所在这个城市的上空，有十几只鸽子背着小背包忙碌着，你不要以为这是信鸽在送邮件。这些鸽子可不简单，它们正在执行一项颇有价值的公共服务。

    ④原来，伦敦环保局为了实时监测城市上空空气质量，一个叫皮埃尔的总工程师突发奇想，他想到了战争时期的信鸽，两次世界大战期间，鸽子都曾被用来传递信息、拯救生命。鸽子的飞行高度相对较低，大约在30到46米之间，时速高达129公里。于是，他想到让鸽子携带空气质量检测仪，对城市上空二氧化氮、臭氧等污染物进行实时检测，而且鸽子还不会受伦敦交通拥堵的影响。他还为自己的计划起了一个好听的名字，叫“鸽子空气巡警队”。

    ⑤很快，他们设计了给鸽子背的专用背包，背包里装载着轻量级污染监测传感器，重量仅为25克。参加计划的鸽子都是赛鸽，由英国著名的鸽子育种师布莱恩·伍德豪斯提供。这些受过训练的鸽子将会在当天带着搜集到的资料回巢。由鸽子搜集的数据通过社交网站推特发布，伦敦市民只需要关注账号并发送他们的位置，鸽群中的一只就会立刻给予反馈，告诉他们所在区域的空气污染指数。

    ⑥如今，伦敦上空每日出现的“鸽子空气巡警队”，成为了这个城市一道亮丽的风景线。它不仅快速有效地向伦敦人展现空气污染的影响，而且也极大地提高了公众对大气污染的认识，越来越多的市民开始自觉保护环境卫生。要知道，每年在英国死于空气污染的人数高达___万人。

    ⑦谈到自己的这一成功计划，皮埃尔总结说：“任何人、任何东西都无法像鸽子那样在伦敦城内快速穿梭、监测空气质量，比如无人机无法穿越整座城市，特别是在上班高峰期，那时的空气污染是最致命的。一直以来，鸽子擅长将重要的信息传递给人类。我正准备在世界其他城市开展鸽子巡警计划，让更多的鸽子同空气污染作战，为人类造福。”

    ⑧他山之石，可以攻玉。我们城市的上空，何时能够见到鸽子这样一支特殊部队来为我们监测空气的品质，提供大气污染数据呢？

（选自2016年11月02日《木木文摘》）