题干

生物圈中由于不同地域的环境差别很大,导致生物的种类也是多种多样的,也由此构成了不同的生态系统.由于人口密集,排放的污水、废气和固体废弃物多,容易产生环境问题的生态系统是(    )

A:森林生态系统

B:城市生态系统

C:湿地生态系统

D:农田生态系统

上一题 下一题 0.0难度 选择题 更新时间:2016-11-11 06:30:35

答案(点此获取答案解析)

B

同类题1

阅读议论文《莫远离“深阅读”》,完成下列小题。

    ①在现代社会,网络、手机、电视等传播媒介,极大改变了人们的阅读习惯。人的身体从书斋里解放出来,整个世界都成了书房。与此同时,阅读也变得越来越简单随意,看时一目十行,看后过目即忘——人们常说的“浅阅读”逐渐风行起来。

    ②传播媒介变了,阅读习惯也随之改变,这无可厚非。读书从来都有不同类别,何况“读”总比“毒”和“赌”好,毕竟它能获取信息、提升修养。但是,如果一种拒绝深度的浅阅读借助于媒介的力量,逐渐演化成社会上大多数人尤其是年轻一代的阅读习惯时,我们是否该有所审视?

    ③阅读之深浅,并非小事。往小里说,涉及个人生活方式,往大处讲,涉及社会风尚和全民族的文化倾向。科技的发达,资讯的浩繁,并不能成为远离深阅读的借口。历史上很多名人,并不苛求读书之多,却强调读书之深。唐宋八大家的韩愈自述所服膺之书不过数种。清代名臣曾国藩反复强调读书要专,“穷经必专一经,不可泛鹜”,“但一部未完,不可换他部,此万万不易之道”。古人讲究读书譬若掘井,与其多掘数井而不及泉,不如专守一井,力求及泉,而用之不竭。当然,一味艰深不免乏味,但是一股脑跟风“浅阅读”,则终会流于浮泛。

    ④我相信,如果沉迷于新潮时尚、“触手可及”的手机阅读、广告阅读、网络阅读,这个社会能够造就千千万万个信息受众,但是很难培育精深广博的大家。当然,这里并非要提倡复古读经,也不是强求每个人都去做名人大家,而只是为时下偏颇式的阅读状况担忧,为人们对这样的阅读习惯习焉不察而担忧。阅读可以是休闲、娱乐,但不应止于休闲、娱乐,尤其是对于整个国民而言。

    ⑤从另一角度来说,人类文明长河存在无数经典,不少作品的孕育时间与创作艰辛都令人慨叹。《红楼梦》披阅十载,增删五次,               这些作品呼唤代代后人不断重读,温故知新。它们的厚重与丰富,也注定了阅读的艰难与沉潜,这是浅阅读无法涉足的领域。曾有人在网上搞所谓的世界经典名著快读,把每部名著概括成几十个字的故事梗概,以为这样可以花最少的时间,读最多的名著,简直可以算得上心浮气躁的典型例子。

    ⑥对于不以读书、研究为业的人来说,“浅阅读”未尝不可,但对于整个社会,对于传统文化的传承和民族素质的提升,深阅读万不可废。如果有一天,国人全都沉迷于摩尔庄园、偷菜游戏、手机短信和QQ聊天,那么这还是不是我们?

同类题5

根据短文理解,选择正确答案。

    You never played the video dance game? Now such games are used to help lose weight!

    Like many other teenage boys, Jones loves sports. But at 5 feet, 175 pounds, he found his weight in trouble. His doctor wanted him to lose 50 pounds so that he may be a good football game player by the end of the summer.

    Jones chose the popular Dance Revolution video game at home to increase his activity. He had lost about 10 pounds by changing his diet. Now, after two weeks' playing the game, he has lost another 10!

    A health study is being done by an insurance company. The company hopes that the game will lead to better health and lower costs. “Obesity claims last year cost us $ 77 million. We have to cut those costs,” said a member of the insurance group. The company provides a game console (游戏主机), a dance mat and software for the six-month, $ 60,000 study.

    The study is more than a commercial thing of an insurance company. It is widely supported by physical education and health professionals.

    In West Virginia, 43% of the nearly 6,000 children examined for heart disease risk were considered over-weighted; more than 25% were too fat. “We are in a crisis of childhood obesity not only in West Virginia but in America,” said a researcher.

    Researchers are now looking at the potential for improving effects by using the game. A teacher in West Virginia has been using the video games in her classes since last fall. She reported that the game does improve heart health as well as eye-hand coordination (协调能力), and her students take the video game as a great alternative to jumping rope or ball games.

    The US Education Department is putting the game in 20 schools to control childhood obesity. Well, are you going to try such to dance away your extra weight?