题干

不回收的航天器在使用后,将成为太空垃圾.如图所示是飘浮在地球附近的太空垃圾示意图,下列说法中正确的是(    )

A:离地越高的太空垃圾运行速率越大

B:离地越高的太空垃圾运行角速度越小

C:离地越低的太空垃圾运行周期越大

D:太空垃圾只可能跟同一轨道上的航天器相撞

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答案(点此获取答案解析)

B

同类题2

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春天忆故人

高红十

    ①春天,第一茬花赶在叶子前扑天抢地地开开;河边柳条摇头晃脑得意地绿;远看有近却无的草坪草,白天黑夜加班长,飞快地长得远看近着一样样绿了。

    ②从遍地毛毛虫,到绿叶满枝头,杨树终究成了扬脸可见像模像样的树,也就眼一闭再睁开的时间。

    ③春季前半季有点慌慌张张,语无伦次,到清明就慢下来了。“清明时节雨纷纷”,虽说雨水不一定清,视线不一定明,但节气这辆吱啊吱啊哼叫的老车毕竟抵达“清明”这重要一站。

    ④那天听广播,正播《我与地坛》,不能不想起文章的作者,走了六七年的史铁生。我和他同在黄土地插队,我延长,他延川,两县挨着,插队时并不认识。文学新时期初起,我在陕西人民出版社编辑文学期刊《绿原》,通过友人介绍,向史铁生约稿。他给我写街道福利小厂的短篇小说《午餐半小时》,似乎没用,也约了赵振开(北岛)的中篇小说《波动》,和前苏联小说《第四十一》,似乎也没用......过去快四十年。

    ⑤我去过他在瘫和宫也就是地坛附近的家,见过他父亲和妹妹。上个世纪八十年代初期,我上第七期文学讲习所(鲁迅文学院前身),一人到他家来过,和同学一起来过。不知坐在轮椅上的史铁生控制哪个机关,院门应声打开,客人得以进了院门又进了房门。《我的遥远的清平湾》获全国优秀短篇小说奖,除了清新的陕北风光,文字表达也十分别致,想哪写哪,散文式的,随意,放得开又收得拢。我问他,怎么这样写?学谁?他有点不好意思,说,鲁迅。

    ⑥后来,和陶正一起上史铁生新搬的家,请他参加一家公司准备拍摄的讲述插队生活的电视剧,电视剧故事除了土插队,还要延伸至出国洋插队。我们很有诚意地和史铁生一道,轮椅出门,轮椅上出租,轮椅下出租,轮椅进楼上电梯直至“走”到谈事的房间……结果是未遂,关于电视剧的理解双方差得有点远。

    ⑦再后来,有了今文坛惊艳的《我与地坛》。他说,在出入地坛十五年后写下此文。可见他出入地坛的第一年至第许多年,一定没为文体事先设计,没有想到是写一篇小散文还是大散文,是文化散文,还是争取获奖的散文,或者不吝文体又像写小说(写园子里一对老夫妇和一位练习唱歌的年轻人那章),史铁生只是把心中想写特别想写的生末净旦丑狮子老虎狗山水林田路……一一铺陈纸笔。

    ⑧文章写了对母亲的愧疚,又岂止是愧疚?写了对生与死的理解,特别悟到死是迟早的事,着什么急一令人顿悟;特别精彩的是园中四季与林林总总的对应,与一天之光景对应,与乐器的对应,与声响的对应,与园中景观的对应,与心绪的对应,与艺术形式对应,与梦的对应……有些对应可能在史铁生出入地坛时就有了,像春草冒芽,像风吹过几片叶脉好看的落叶那时就有了文章的碎片。要不是觉得结构、段落排序、语言风格基本成熟可以动笔,还会有什么对应四季的奇思妙想源源不断无限铺排开来。

    ⑨十五年出入地坛,史铁生是在深入生活么?眼下不少采风式的“深入生活”只能叫擦蹭生活,史铁生似乎高于深入生活。清明时节听此文,一种情感的、文学的浸润,浸润干涸的世道,浸润干涸世道里粗戾的人心。那文字,像摩挲把玩许久许久的手事,都润泽成玉了。相比有的人人没走,文字就旧了,颓了,蔫巴了。《我与地坛》的作者走了六七年,被广播里的专业人士读起来,新鲜有如古筝铮铮作响,清亮无比,深沉无比,余音袅袅。难得的是《我与地坛》全文几无废话,这年头,要想说或者写一些没有废话的话,该是多难的事!

    ⑩春天来了,春天读好文章,情随声来,声情并茂。春天听好文章,万物生发思念也生发,万物綻放情感也绽放,带起听者所有感觉,却无悲伤。文章在,人就在,文章好好活着,人也就好好活着,并且好好活下去。

    ⑪记得有一年,史铁生从延安回来,晒得有点黑,他叫着我的名字,欢喜地对我说,延安有人问你好呢……

(选自《北京日报》2017 年04月27日,有删改)

同类题4

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       The earth is dying before us yet we sit and watch. If the TV or the game system breaks, we run off to the stores to get it fixed immediately no matter what the cost. Why aren't we willing to fix our earth? Are our televisions and game systems more important to us than where we live? Where shall we continue to live, until the end of time?

       The earth is our home and cannot be replaced. We must take care of it. We have come up with so much technology that limits us instead of helping us. Take that game system we run to repair. What does it do? It occupies kids' time! The earth has already given kids plenty of entertainment in the forms of fields and hills, forests and plains, water and land. However, instead of using what the earth has given us, and helping kids by giving them exercise as they run around, we decide to ruin kids' minds with game systems that glue them to the screen for hours, and make them ignore their homework and chores. We have polluted this earth by making these things which do not even help in any way!

       We have already messed up this world; we have ruined the air, water, and animals that it has so willingly provided for us. We need to stop this destruction of life and bring back the world we had before. It will not be easy, but everybody can help! What about something as simple as turning the lights off when you leave a room? Recycling what can be recycled? Picking up litter? Donating money to an environmental organization? None of these things are very hard. We can't just always say, “Oh, the earth is a mess. Ah, well, those big companies that are polluting so much can stop and fix it.” Instead, we need to help out. It's not only those big companies; it's everyday things that we do too that are ruining the earth. So stop and think about what you can do to make a difference to our world!