下列属于群落的是() A.一座水库里的全部鱼 B.一个湖泊中藻类、鱼类、蚌等全部生物

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问题:

下列属于群落的是()

A.一座水库里的全部鱼

B.一个湖泊中藻类、鱼类、蚌等全部生物

C.一片草原上昆虫和小鸟

D.一棵枯树以及上面的苔藓、真菌等

考点:高中生物种群和群落种群和群落题库
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(8分)2010年7月21日是人民币汇率形成机制改革五周年的日子。五年以来,人民币汇率形成机制改革按照主动性、渐进性、可控性原则有序推进,我国政府采取保持人民币币值基本稳定,积极稳妥地进行人民币汇率改革。2008年4月18日,100美元兑换698.36元人民币。2010年10月22日,100美元兑换664.85元人民币。

运用所学的经济生活知识回答:

(1)与2008年4月18日相比,2010年10月22日美元对人民币的汇率发生了什么变化?这种变化意味着什么?(4分)

(2)我国保持人民币币值基本稳定有何意义?(4分)

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下列从左到右的变形是分解因式的是(  )
A.3x+3y-5=3(x+y)-5B.(x+1)(x-1)=x2-1
C.x2-9=(x+3)(x-3)D.x+1=x(x+
1
x
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温度对金属材料强度及塑性影响很大,一般温度升高,金属的强度会(),但它的()却提高。

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“This is a really exciting time — a new era is starting,” says Peter Bazalgette, the chief creative officer of Endemol. He is referring to the upsurge of interest in mobile television, a nascent industry at the intersection of telecoms and media which offers new opportunities to device-makers, content producers and mobile-network operators. And he is far from alone in his enthusiasm.

Already, many mobile operators offer a selection of television channels or individual shows, which are “streamed” across their third-generation (3G) networks. 41. ______.

Meanwhile, Apple Computer, which launched a video-capable version of its iPod portable music-player in October, is striking deals with television networks to expand the range of shows that can be purchased for viewing on the device, including “Lost”, “Desperate Housewives” and “Law & Order”.

42. ______. For a start, nobody really knows if consumers will pay for it, though surveys suggest they like the idea. Informa, a consultancy, says there will be 125m mobile-TV users by 2010. But many other mobile technologies inspired high hopes and then failed to live up to expectations. And even if people do want TV on the move, there is further uncertainty in two areas: technology and business models.

At the moment, mobile TV is mostly streamed over 3G networks. But sending an individual data stream to each viewer is inefficient and will be unsustainable in the long run if mobile TV takes off. 43. ______.

44. ______. That suggests that some shows (such as drama) better suit the download model, while others (such as live news, sports or reality shows) are better suited to real-time transmission. The two approaches will probably co-exist.

Just as there are several competing mobile-TV technologies, there are also many possible business models. Mobile operators might choose to build their own mobile-TV broadcast networks; or they could form a consortium and build a shared network; or existing broadcasters could build such networks.

The big question is whether the broadcasters and mobile operators can agree how to divide the spoils, assuming there are any. Broadcasters own the content, but mobile operators generally control the handsets, and they do not always see eye to eye. 45.

Then there is the question of who will fund the production of mobile-TV content: broadcasters, operators or advertisers Again, the answer is probably “all of the above”.

[A] So the general consensus is that 3G streaming is a prelude to the construction of dedicated mobile-TV broadcast networks, which transmit digital TV signals on entirely different frequencies to those used for voice and data. There are three main standards: DVB-H, favoured in Europe; DMB, which has been adopted in South Korea and Japan; and MediaFLO, which is being rolled out in America. Watching TV using any of these technologies requires a TV-capable handset, of course.

[B] In contrast, watching downloaded TV programmes on an iPod or other portable video player is already possible today. And unlike a programme streamed over 3G or broadcast via a dedicated mobile-TV network, shows stored on an iPod can be watched on. an underground train or in regions with patchy network coverage.

[C] In South Korea, television is also sent to mobile phones via satellite and terrestrial broadcast networks, which is far more efficient than sending video across mobile networks. In Europe, the Italian arm of 3, a mobile operator, recently acquired Channel 7, a television channel, with a view to launching mobile-TV broadcasts in Italy in the second half of 2006.

[D] Despite all this activity, however, the prospects for mobile TV are unclear.

[E] Assuming the technology and the business models can be sorted out, there is still the tricky matter of content.

[F] In South Korea, a consortium of broadcasters launched a free-to-air DMB network last month, but the country’s mobile operators were reluctant to provide their users with handsets able to receive the broadcasts, since they were unwilling to undermine the prospects for their own subscription-based mobile-TV services.

[G] The potential for mobile TV is vast, in short — but so is the degree of uncertainty over how it should actually be put into practice.

43()

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病鱼皮肤上出现苍白块斑与水疱,全身多处明显出血,特别是嘴、腹部、尾鳍,鳃丝腐烂、出血,分泌大量黏液或出现块斑状组织坏死的病可能是()

A.传染性造血器官坏死病

B.病毒性神经坏死病

C.锦鲤疱疹病毒病

D.流行性造血器官坏死病

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