托福阅读模拟试题及答案卷四.docx

1、托福阅读模拟试题及答案卷四2020年托福阅读模拟试题及答案（卷四） 托福阅读文本：Scientists have discovered that for the last 160,000 years, at least, there has been a consistentrelationship between the amount of carbon dioxide in the air and the average temperature of theplanet. The importance of carbon dioxide in regulating the Earths t

2、emperature was confirmed byscientists working in eastern Antarctica. Drilling down into a glacier, they extracted a mile-longcylinder of ice from the hole. The glacier had formed as layer upon layer of snow accumulatedyear after year. Thus drilling into the ice was tantamount to drilling back throug

3、h time.The deepest sections of the core are composed of water that fell as snow 160,000 years ago.Scientists in Grenoble, France, fractured portions of the core and measured the composition ofancient air released from bubbles in the ice. Instruments were used to measure the ratio of certainisotopes

4、in the frozen water to get an idea of the prevailing atmospheric temperature at the timewhen that particular bit of water became locked in the glacier.The result is a remarkable unbroken record of temperature and of atmospheric levels of carbondioxide. Almost every time the chill of an ice age desce

5、nded on the planet, carbon dioxide levelsdropped. When the global temperature dropped 9F (5 C), carbon dioxide levels dropped to 190parts per million or so. Generally, as each ice age ended and the Earth basked in a warminterglacial period, carbon dioxide levels were around 280 parts per million. Th

6、rough the 160,000years of that ice record, the level of carbon dioxide in the atmosphere fluctuated between 190 and280 parts per million, but never rose much higher-until the Industrial Revolution beginning in theeighteenth century and continuing today.There is indirect evidence that the link betwee

7、n carbon dioxide levels and global temperaturechange goes back much further than the glacial record. Carbon dioxide levels may have beenmuch greater than the current concentration during the Carboniferous period, 360 to 285 millionyears ago. The period was named for a profusion of plant life whose b

8、uried remains produced alarge fraction of the coal deposits that are being brought to the surface and burned today.托福阅读题目：1. Which of the following does the passage mainly discuss?(A) Chemical causes of ice ages(B) Techniques for studying ancient layers of ice in glaciers(C) Evidence of a relationsh

9、ip between levels of carbon dioxide and global temperature(D) Effects of plant life on carbon dioxide levels in the atmosphere2. The word accumulated in line 6 is closest in meaning to.(A) spread out(B) changed(C) became denser(D) built up3. According to the passage , the drilling of the glacier in

10、eastern Antarctica was important becauseit(A) allowed scientists to experiment with new drilling techniques(B) permitted the study of surface temperatures in an ice-covered region of Earth(C) provided insight about climate conditions in earlier periods(D) confirmed earlier findings about how glacier

11、s are formed4. The phrase tantamount to in line 7 is closest in meaning to(A) complementary to(B) practically the same as(C) especially well suited to(D) unlikely to be confused with5.According to the passage , Grenoble, France, is the place where(A) instruments were developed for measuring certain

12、chemical elements(B) scientists first recorded atmospheric levels of carbon dioxide(C) scientists studied the contents of an ice core fromAntarctica(D) the relationship between carbon dioxide and temperature was discovered6. According to the passage , scientists used isotopes from the water of the i

13、ce core to determinewhich of following?(A) The amount of air that had bubbled to the surface since the ice had formed(B) The temperature of the atmosphere when the ice was formed(C) The date at which water had become locked in the glacier(D) The rate at which water had been frozen in the glacier7. T

14、he word remarkable in line 14 is closest in meaning to(A) genuine(B) permanent(C) extraordinary(D) continuous8. The word link in line 23 is closest in meaning to(A) tension(B) connection(C) attraction(D) distance9. The passage implies that the warmest temperatures among the periods mentioned occurre

15、d(A) in the early eighteenth century(B) 160,000 years ago(C) at the end of each ice age(D) between 360 and 285 million years ago10.According to the passage , the Carboniferous period was characterized by(A) a reduction in the number of coal deposits(B) the burning of a large amount of coal(C) an abundance of plants(D) an accelerated rate of glacier formation11. The passage explains the origin of which of the following terms?(A) glacier (line 5)(B) isotopes (li