相关考题
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填空题
细胞核在结构和功能上可分为四个区，分别是（）、（）、（）、（）。 -
单项选择题
根据短文回答 41～45 题。 A Thirsty World The world is not only hungry; it is also thirsty for water. This may seem strange to you, since nearly 75% of the earth's surface is covered with water. But about 97% of this huge amount is sea-water, or salt water. Man can only drink and use the other 3% - the fresh water that comes from rivers, lakes, underground, and other sources. And we cannot even use all of that, because some of it is in the form. of icebergs (冰山) and glaciers (冰川). Even worse, some of it has been polluted.At the moment, this small amount of fresh water is still enough for us. However, our need for water is increasing rapidly. Only if we take steps to deal with this problem now can we avoid a severe worldwide water shortage later on. A limited water supply would have a bad effect on agriculture and industry.In addition to stopping wasting our precious water, one useful step we should take is to develop ways of reusing it. Experiments have already been done in this field, but only on a small scale.Today, in most large cities, water is used only once and it eventually returns to the see or runs into underground storage tanks. But it is possible to pipe water that has been to a purifying (净化)' plant. There it can be filtered (过滤) and treated with chemicals so that it can be used again just as if it ware fresh from a spring. But even if every large city purified and reused its water, we still would not have where could we turn next? To the oceans! All we d have to do to make use of vast amount of sea-water is - remove the salt. This salt-removing process is already use in many parts of the world.So if we take all these steps, we'll be in no danger of drying up ! 第 41 题 The phrase 'the world' in the first line of the passage refers to（ ）A．'man'B．'you'C．'woman'D．'they'
A.
At
B.
In
C.
Today,
D.
So
E.'man'
B．'you'
C．'woman'
D．'they' -
单项选择题
根据短文回答 23～30 题。 Global Warming 1 Smoke is clouding our view of global warming, protecting the planet from perhaps three-quarters of the greenhouse (温室) effect. That might sound like good news, but experts say that as the cover diminishes in coming decades, we are. facing a dramatic increase of warming that could be two or even three times as great as official best guesses.2 This was the dramatic conclusion reached last week at a workshop in Dahlem, Berlin, where top atmospheric scientists got together, including Nobel Prize winner Paul Crutzen and Swedish scientist Bert Bolin, former chairman of the UN's Intergovemmental Panel on Climate Change (IPCC).3 IPCC scientists have suspected for a decade that aerosols (浮质) of smoke and other particles from burning rainforest, crop waste and fossil fuels are blocking sunlight and counteracting the warming effect of carbon dioxide (二氧化物) emissions. Until now, they reckoned that aerosols reduced greenhouse warming by perhaps a quarter, cutting increases by 0.2~C． So the 0.6~C of warming over the past century would have been 0.8~C without aerosols.4 But the Berlin workshop concluded that the real figure is even higher--aerosols may have reduced global warming by as much as three-quarters, cutting increases by 1.8~C． If so, the good news is that aerosols have prevented the world getting almost two degrees warmer than it is now. But the bad news is that the climate system is much more sensitive to greenhouse gases than previously guessed.5 As those gases are expected to continue accumulating in the atmosphere while aerosols stabilize or fall, that means 'dramatic consequences for estimates of future climate change', the scientists agreed in a draft report from the workshop. 第 23 题 Paragraph 2______________A．Atmospheric ScientistsB．The Calculations Made at the Berlin WorkshopC．The Previous Calculations of the Effect of AerosolsD．The Scientists'AgreementE．The Authoritative ConclusionF．Greenhouse Gases
A.
2
B.
3
C.2~C．
D.6~C
E.8~C
F.
4
G.8~C．
H.
5
I.Atmospheric
J.The
K.The
L.The
M.The
N.Greenhouse
