2011雅思阅读模拟试题精选9_第2页

10  Ehrlich concedes this. "If there is a way to test this theory on the sun， I can't think of one that is practical，" he says. That's because variation over 41，000 to 100，000 years is too gradual to be observed. However， there may be a way to test it in other stars： red dwarfs. Their cores are much smaller than that of the sun， and so Ehrlich believes that the oscillation periods could be short enough to be observed. He has yet to calculate the precise period or the extent of variation in brightness to be expected.

　　11  Nigel Weiss， a solar physicist at the University of Cambridge， is far from convinced. He describes Ehrlich's claims as "utterly implausible". Ehrlich counters that Weiss's opinion is based on the standard solar model， which fails to take into account the magnetic instabilities that cause the temperature fluctuations.（716 words）

　　Questions 1-4

　　Complete each of the following statements with One or Two names of the scientists from the box below.

　　Write the appropriate letters A-E in boxes 1-4 on your answer sheet.

　　A.     Attila Grandpierre B.     Gábor ágoston C.     Neil Edwards D.    Nigel Weiss E.     Robert Ehrlich

　　1. ……claims there抯 a dimmer switch inside the sun that causes its brightness to rise and fall in periods as long as those between ice ages on Earth.

　　2. ……calculated that the internal solar magnetic fields could produce instabilities in the solar plasma.

　　3. ……holds that Milankovitch cycles can induce changes in solar heating on Earth and the changes are amplified on Earth.

　　4. ……doesn't believe in Ehrlich's viewpoints at all.

　　Questions 5-9

　　Do the following statements agree with the information given in the reading passage？

　　In boxes 5-9 on your answer sheet write TRUE     if the statement is true according to the passage FALSE    if the statement is false according to the passage NOT GIVEN    if the information is not given in the passage

　　5. The ice ages changed frequency from 100，000 to 41，000 years a million years ago.

　　6. The sole problem that the Milankovitch theory can not solve is to explain why the ice age frequency should shift from one to another.

　　7. Carbon dioxide can be locked artificially into sea ice to eliminate the greenhouse effect.

　　8. Some scientists are not ready to give up the Milankovitch theory though they haven't figured out which mechanisms amplify the changes in solar heating.

　　9. Both Edwards and Ehrlich believe that there is no practical way to test when the solar temperature oscillation begins and when ends.

　　- Questions 10-14

　　Complete the notes below.

　　Choose one suitable word from the Reading Passage above for each answer.

　　Write your answers in boxes 10-14 on your answer sheet.

　　The standard view assumes that the opposing pressures of gravity and nuclear fusions hold the temperature ……10……in the sun's interior， but the slight changes in the earth's ……11…… alter the temperature on the earth and cause ice ages every 100，000 years. A British scientist， however， challenges this view by claiming that the internal solar magnetic ……12…… can induce the temperature oscillations in the sun's interior. The sun's core temperature oscillates around its average temperature in ……13…… lasting either 100，000 or 41，000 years. And the  ……14…… interactions within the sun's magnetic field could flip the fluctuations from one cycle length to the other， which explains why the ice ages changed frequency a million years ago.

　　Answer keys and explanations：

　　1. E See the sentences in paragraph 1（There's a dimmer switch inside the sun that causes its brightness to rise and fall on timescales of around 100，000 years - exactly the same period as between ice ages on Earth. So says a physicist who has created a computer model of our star's core.） and para.2 （Robert Ehrlich of George Mason University in Fairfax， Virginia， modelled the effect of temperature fluctuations in the sun's interior.）

　　2. A B See para.3： ？i style='mso-bidi-font-style： normal'>Grandpierre and a collaborator， Gábor ágoston， calculated that magnetic fields in the sun's core could produce small instabilities in the solar plasma.