2014年雅思阅读练习题及答案13_第2页

　　1....claims there 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='magnetic fields in the sun's core could produce small instabilities in the solar plasma.These instabilities would induce localised oscillations in temperature.

　　13.cycles

　　See para.4：…allow the sun's core temperature to oscillate around its average temperature of 13.6 million kelvin in cycles lasting either 100,000 or 41,000 years.

　　14.random

　　See para.4：Ehrlich says that random interactions within the sun's magnetic field could flip the fluctuations from one cycle length to the other.