题干

黄土高原是中国生态环境最脆弱的地区之一,该地区人地矛盾突出,治理黄土高原,改善生态环境,已成为人们的共识.黄土高原人地关系十分尖锐的根本原因是( )

A:经济发展速度过快,资源开采过多

B:工业污染日益加重

C:工业结构不合理导致环境破坏

D:人口增长过快过多,导致生态、经济恶性循环

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D

同类题2

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    Do you and your friends ever talk about your dreams with each other? If you do, you might have noticed something interesting – some of your friends seldom remember their dreams, but some can always describe their dreams so clearly that it seems like they're describing things that really happened to them. What makes those people different?

    The answer is simple. There are two different types of dreamers – low dream recallers(回忆者)and high dream recallers.

    Low dream recallers usually remember their dreams only twice a month. But high dream recallers are able to remember them about five mornings a week. And a new study suggests that activity in a certain part of the brain could have something to do with it, reported The Huffington Post.

    Perrine Ruby, a French researcher at the Lyon Neuroscience Research Center, studied 41 people (21 high dream recallers and 20 low dream recallers) and recorded their brain activity.

    She found that a part of the brain called the temporo-parietal junction (颞顶联合区) was more active in high dream recallers than in low dream recallers – both when they were sleeping and awake.

    This brain area collects and processes(编程)information from the outside world. This means that high dream recallers know more about what's happening around them. For example, when they are awake, they respond (对……有反应) more strongly to hearing their own names, and when they are sleeping, they are woken more easily by sounds and movements.

    By closely studying people's brain activities, Ruby found that high dream recallers have twice as much “wakefulness time” during sleep as low dream recallers do. And it is during these short times of wakefulness that the brain remembers dreams.

    “The sleeping brain is not able to remember new information,” Ruby told The Washington Post. “It needs to wake up to be able to do that.”

    This is not hard to understand. Just try to think of your own sleeping experiences. If you are worried during the night, you are more likely to remember your dreams, but if you sleep well, you will remember little in the morning, and this is because “you never get a chance to remember”, Robert Stickgold, a Harvard Medical School researcher, told The Washington Post.

同类题4

课外精选美文阅读。

最暖心的事

美国鲍勃·布劳顿

    ①十年前,我从得克萨斯州的乡村来到纽约开出租车谋生。开的士会看到形形色色的人,有的人幽默诙谐,有的人失意忧郁,还有的人自命不凡。但让我印象最深的莫过于一个老太太。

    ②那是今年5月份第2个星期日的深夜,我接到城郊的一个要车的电话。我想,也许是一些参加完晚会的人,或是某个刚赶到这个城市过母亲节的人。

    ③我到达目的地时是3点30分。一个破败的公寓楼黑黢黢地立在我的眼前,只有一楼有一个房间透出一点灯光。这种情况下,大多数司机顶多只会按一两声喇叭,稍等片刻,然后开车走人。因为这个时间和地点时常会出现治安问题。然而,我也知道这个时间在这样的地方打车不易,再说也许这个客人有点困难需要我帮一把手呢。于是,我走到亮灯的那户人家敲了敲门。

    ④“等一会儿。”回答我的是一个苍老虚弱的声音。我听到屋内有什么东西在地上拖动。隔了好久,门开了,一个80多岁的瘦小的老太太吃力地拖着一个萨斯包走了出来。她身穿一件印第安大花布上衣,头戴一顶圆桶形帽子,帽子上还罩了一条面纱,活脱脱是一个上世纪四十年代好莱坞电影里走出的人物。

    ⑤“你能帮我拾一下包吗?”她说。我先将她的包拎上车子,然后又回头搀扶着她。她走得很慢,边走边对我感谢不尽。

    ⑥“这没什么。”我说,“我这是为我的客人服务。再说,我希望我的妈妈在外面也能得到同样的服务。”

    ⑦“你真是一个好人。”她说。进了车子,她给了我一个地址,问:“能不能从城里走?我很想再看看这座城市……”

    ⑧“能,不过这就不是最近的路了。”我答道。

    ⑨“这不要紧。”她说,“我不着急。我是菲奥娜小姐,不过人们都叫我菲奥娜太太,是去圣洛安敬老院口”

    ⑩我从后视镜中看了她一眼。菲奥娜太太的眼窝里有一滴亮晶晶的东西。“我孤寡一人。”她继续说道,“医生说,我剩下的时间不多了。不然我不会去的。”

    ⑪我悄悄地伸手关掉了计程表。经过城里的路程一刻钟就能走完,然而我们却花了足足有两个多小时,因为她一会儿让我慢行,一会儿让我停车,还不时地讲着话。菲奥娜太太指着一座大楼,告诉我她曾在这儿干过电梯操作员的工作。在经过一个居民区时,她说她和丈夫结婚的新房就是在这里。她要我将车子在一个商场前停了一会儿。她说这里曾是个舞厅,年轻时她在舞厅当过舞蹈指导老师。有时,她会让我在某一个地方放慢速度,然后默默凝视前方,一句话也不说。

    ⑫当第一缕阳光露出地平线的时候,菲奥娜太太这才说:“我累了。走吧。”

    ⑬车子来到了她要去的圣洛安敬老院前。敬老院的两个工作人员正在等着我们,工作人员说:“这位老太太一直不肯来敬老院,现在她患了肺癌,才同意来敬老院,而且必须在今年的母亲节来敬老院。”工作人员说着给她推来了轮椅。

    ⑭“我应该付给你多少钱?”菲奥娜太太取出钱包问我。

    ⑮“不要钱。”我答道。

    ⑯“你也要养家。”菲奥娜说。

    ⑰“还有其他客人呢。”我说,接着几乎是不假思索地弯下腰拥抱了她。她紧紧地抱住我。“你给了一个老太太一小会儿快乐的时光。”她说,“谢谢你。”

    ⑱我最后握了一握她的手,然后走向暗淡的晨曦。我的身后响起了关门的声音。这是一个即将结束的生命发出的声音。一路上,我在想,如果今天带菲奥娜太太的是一个脾气急躁没有耐心的司机,如果我在公寓楼前按一二声喇叭后就把车开走,又会是怎样一种情形呢?

    ⑲我做的这件事情似乎微不足道,但是现在想起来,却是我一生中最暖心的一件事情。

 (选自《青年文摘》,有改动)