C

Alaska’s Arctic lakes now freeze later and melt earlier in the year than in 1950，leaving them easy to suffer water loss from evaporation(蒸发)and possibly adding to local warming，a new study finds．The winter ice season near Barrow，Alaska，is shorter than in 1950, researchers reported Jan．30 in the journal The Cryosphere.

Lake ice is also thinner each winter．The scientists surveyed 402 lakes on the North Slope，where permafrost (permanently frozen ground)and shallow lakes dominate the area．In 2011，the lake ice was 38 percent thinner than in 1950，and 22 percent fewer lakes froze through to their bottoms．

“When we saw the actual numbers we were shocked at how dramatic the change has been，”lead study author Cristina Surdu，of the University of Waterloo in Canada，said in a statement．Surdu and her co-authors analyzed the changes in lake—ice thickness and ice cover with satellite images and climate model simulations(satellite images are only available from 1991)．

The climate models suggest the Arctic lakes froze almost six days later and broke up about 18 days earlier in the winter of 2011 compared with the winter of 1950．“The changes in ice and the shortened winter affect Northern communities that depend on ice roads to transport goods，”Surdu said．For example，every winter，oil companies build roads over frozen lakes to carry supplies to Prudhoe Bay．

‘‘The dramatic changes in lake ice may also contribute to further warming of the entire region，because open water on lakes contributes to warmer air temperatures，”Surdu said．The Arctic is warming twice as fast as the rest of the planet，for reasons that may include its layered atmosphere，which traps heat，and the loss of sea ice and snow cover，which help reflect the sun’s energy when present．

51．What does the text mainly tell us?

    A．Arctic 1akes now freeze earlier and melt 1ater．

    B．Alaska’s local warming is decreasing sharply．

    C．Arctic lakes are losing ice．

    D．Arctic lakes hold more flesh water than before．

52．What can we infer the North Slope is dotted with?

    A．thick forests．    B．numerous lakes．

    C．green grasslands．D．fertilized farmlands．

53．According to the text，the great changes of Alaska’s Arctic lakes _____________．

    A．are totally beyond Surdu’s expectations

    B．are completely within Surdu’s expectations

    C．come as no surprise to Surdu and her co-authors

    D．come as a great excitement to Surdu

54．How many days was the winter ice season of Arctic 1akes in 2011 shorter than that in 1950?

    A．6 days．    B．12 days．    C．18 days． D．24 days．

55．What is the last paragraph mainly about according to Surdu?

    A．What reflects the sun’s energy．

    B．How its layered atmosphere traps heat．

    C．Why our planet is warming．

    D．Why the Arctic region is becoming warmer．

D

Britain’s private schools are one of its most successful exports．The children of the well-off flock to them，whether from China，Nigeria or Russia ：the number of foreign pupils rose by 1.4％in the last year alone．

Yet foreign students，whether educated in British private schools or elsewhere，are decreasingly likely to go to English universities．According to the Higher Education Funding Council for England，307,200 overseas students began their studies in the country in 2012-13，down from 312，000 two years earlier and the first drop in 29 years．Student numbers from the rest of the European Union(EU)fell—probably a result of the increase in annual tuition fees in England from ￡6，000(＄10，000)a year to ￡9，000．But arrivals from India and Pakistan declined most sharply．

In contrast to the visa system for private schools，which is extremely loose(the Home Office counts private schools as favoured sponsors)，student visas have been tightened．Foreign students used to be allowed to work for up to two years after graduating．They now have only four months to find a job paying up to ￡20，600 if they want to stay in Britain．

This change was intended to deal with fake colleges offering two-year work visas．But it seems to have put off serious students too．Nick Hillman of the Higher Education Policy Institute says the government has sent unclear messages about the sort of immigration it wants to restrict．Australia and America，which have more relaxed entry criteria for students，are becoming more favoured destinations．

Britain’s student-visa system bas become more onerous(繁琐) overall．As a result，Britain is losing out to other countries in the contest for talent．Its unwelcoming attitude will harm its long-term development．And the drift of foreign students from leading British private schools to American colleges may have another, somewhat happier，consequence：America might become rather better at cricket(板球)．

56．What causes the foreign student numbers to English universities to drop?

A．Poor quality of higher education．

B．The sharp increase of tuition fees．

C．The poor economic situation in EU．

D．Higher living cost in England．

57．What’s the aim of UK tightening its student visas?

A．To control the student number from India and Pakistan．

B．To increase the financial income of UK．

C．To send clear messages about the sort of immigration．

D．To deal with fake colleges that offer‘two-year work visas．

58．Why is it easy to get the visa from private schools in Britain?

A．Because private schools have bad quality of education．

B．Because graduates from private schools can earn￡20，600．

C．Because private schools turn in more money to the Home Office．

D．Because their students can work for two years after graduating．

59．According to the passage，Britain________．

A．is famous for playing cricket

B．will get more talents in the future

C．will simplify its student-visa system

D．will help US colleges to develop cricket

60．What can we infer from the text?

A．Foreign students are going off English universities．

B．American universities are of higher quality than English ones．

C．Britain’s student-visa system will help its long-term development．

D．Britain’s new student-visa system is popular with foreign students．
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