★★★☆

這篇題目都不難，就看考場上時間夠不夠。

時間就要從填空和短文章里省了~

題型優(yōu)先級判定：

1.The passage is primarily concerned with?主旨目的，首段+各段首句，可以先做

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2.Which of the following describes research that is most clearly analogous to the testing done by GRIP scientists??不同層不同組成體現(xiàn)某個趨勢變化，找到testing就做

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3.According to the passage, which of the following is the most accurate statement of what scientists believed,?prior to the GRIP findings, about Earth’s climate??直接細節(jié)信息，定位第一句，注意審題。

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4.The passage?suggests that which of the following is most likely to have been true of the oxygen-16 and oxygen-18 isotopes found in the?lower sections of the GRIP core??看似考細節(jié)，就看盯不盯得住文章主旨了，需要知道第四段研究結論

文章分析：

para 1:

Based on evidence from tree rings, pollen samples and other records, scientists have for a long time assumed that interglacials—warm interludes between ice ages—were as mild and uniform as the Holocene, the present interglacial, has been for all of its 8,000 to 10,000 years. But new research in Greenland has put this assumption into question.

para 1:?觀點點評，新研究質疑老觀點；

這時候什么題都沒法做。

繼續(xù)讀各段首句。

para 2:

Researchers on two teams, the Greenland Ice-Core Project (GRIP) and the Greenland Ice Sheet?Project 2 (GISP2), have analyzed two different cylinders of ice, each about two?miles in depth, pulled up from the Greenland ice sheet. 做研究

para 3:

Findings from the upper sections of the cores have confirmed what scientists already knew:climate during the last ice age fluctuated rapidly. 得結果

para 4:

Researchers’ clues to the Eemian climate come from measurements of the ratios of two slightly different types of oxygen, isotopes oxygen-16 and oxygen-18, preserved in theGRIP core. 講原理

para 5:

However, finds from the lower section of GISP 2 do not confirm those of GRIP. 有轉折，兩組實驗有不一致。

這時候可以嘗試解第1題主旨題。

1.The passage is primarily concerned with?主旨目的，考結構，先看首段+各段首句

A.refuting?certain scientific theories about Earth’s climatic history 看完選項可以作為備選

（關于refute，如果以這個主旨倒回去寫一篇文章，呈現(xiàn)出來的就不是這篇文章的本來樣子了）沒有證據(jù)

B. outlining new findings concerning Earth’s climate during ice ages?說明文

C. discussing new research that may challenge a long-held scientific assumption about Earth’s climatic history 符合

D.describing the climatic changes that occurred when Earth moved from an ice age into an interglacial period?無關，說明文

E.reconciling conflicting?evidence concerning climatic changes.?無關/沒有證據(jù)

繼續(xù)。

para 2:

Researchers on two teams, the Greenland Ice-Core Project (GRIP) and the Greenland Ice Sheet Project 2 (GISP2), have analyzed two different cylinders of ice, each about two miles in depth, pulled up from the Greenland ice sheet. Such ice cores trap gases, bits of dust, and other chemicals that were present in the snow that fell over Greenland for thousands of years and then became compressed into ice. By studying these components, scientists have obtained a detailed archive of many aspects of climate, including air temperatures, snowfall, and concentrations of greenhouses gases in the atmosphere.

para 2:?介紹新研究內容；

有兩題可做。

2.Which of the following describes research that is most clearly analogous to the?testing done by GRIP scientists??不同層不同組成體現(xiàn)某個趨勢變化

A.Scientists studying the formation of the Sahara desert measure the rate oftopsoil erosion in the region?沒有不同組成

B.Scientists seeking to determine the age of a particular fossil measure thepercentage of its carbon atoms that have decayed?沒有不同組成

C.Scientists researching vision in flies measure and compare the amounts ofvitamin A found in the retinas of several fly species.?（視網膜）沒有不同組成

D.Scientists investigating the development of life on Earth measure and comparethe amount of oxygen used by various organisms along the evolutionary scale.?沒有不同組成

E. Scientists plotting the fluctuationsin rainfall in the early rain forests measure the presence of certain gasestrapped in tree rings of older trees.

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3.According to the passage, which of the following is the most accurate statementof what scientists believed,?prior to the GRIP findings, about Earth’s climate? 這一段實驗做完了。實驗之前的想法也就出來了。直接細節(jié)信息，定位全文第一句，注意審題。

A.Over the course of Earth’s history, interglacials have become?progressively?milder沒有證據(jù)

B.Earth’s?overall climate?has been generally mild since the?planet’s formation?沒有證據(jù)

C.During both interglacials and ice ages, Earth’s climate has fluctuated violently.?相反

D. During ice ages, Earth’s climate has been highly variable, whereas during interglacials it has been mild and stable.

E.During interglacials, Earth’s climate has been highly variable, whereas during ice ages it has been uniformly cold and icy.?相反/沒有證據(jù)

還有一題。

專注找O16 O18就好了。

para 3:

Findings from the upper sections of the cores have confirmed what scientists already knew:climate during the last ice age fluctuated rapidly. But scientists wereastonished by findings from the lower sections of the GRIP core, which provideda close look at an interglacial period other than our own, the Eemian interglacial, a period that lasted from 135,000 to 115,000 years ago. Data from GRIP seem to indicate that the Eemian climate swung at least as wildly as theclimate of ice age periods.

para 4:

①Researchers’ clues to the Eemian climate come from measurements of the ratios of two slightly different types of oxygen, isotopes oxygen-16 and oxygen-18, preserved in the GRIP core. ②These ratios register the fluctuations of air temperatures over the seasons and years. ③When the air was warm, vapor containing the heavier isotope, oxygen-18, condensed and formed precipitation, in the form of snow, more readily than did vapor containing oxygen-16.?④Thus, snow that fell during warmer periods contains proportionally more oxygen-18 than snow deposited during cold spells. ⑤Evidence of rapid climate shifts was also drawn from other sources, such as measurements of amounts of dust and calcium ions in the ice layers during cold periods: winds were strong, causing calcium-rich dust from loess deposits,which are composed of loose surface sediment, to blow across the ice sheet.Thus, differing amounts of dust in the layers also indicate changing climatic conditions.

para 5:

However, finds from the lower section of GISP 2 do not confirm those of GRIP. The wild climates wings shown by GRIP in the last interglacial are not seen in the GISP2 core. According to a GISP 2 scientist, the weight of flowing glacial ice above has stressed the lower sections of both cores. This may have deformed the lower ice, disrupting its annual layers and thereby causing the discrepancy between the records.?Still, some climatologists believe GRIP’s record may be the more reliable of the two. It was drilled closer to a location called the ice divide, where stresses would have been lower, they say.

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4.The passage?suggeststhat which of the following is most likely to have been true of the oxygen-16 and oxygen-18 isotopes found in the?lower sections of the GRIP core??看似考細節(jié)，就看盯不盯得住文章主旨了，需要知道第四段研究結論

A.There was significantly more isotope oxygen-18 than isotope oxygen-16 in theice layers.?無證據(jù)

B.There was significantly more isotope oxygen-16 than isotope oxygen-18 in theice layers.?無證據(jù)

C. Ratios of isotopes oxygen-18 and oxygen-16 varied in the ice layers.

D.Layers containing isotope oxygen-18 placed stress on the layers containing isotope oxygen-16, possibly distorting them.?無證據(jù)

E.Isotope oxygen-16, being lighter, was located mainly in the upper layers, whereas oxygen-18 had settled into the lower layers.?無證據(jù)

背景拓展：

Holocene 全新世

全新世是地質時代最新階段，第四紀二分的第二個世，開始于12000～10000年前持續(xù)至今。這一時期形成的地層稱全新統(tǒng)，它覆蓋于所有地層之上。全新世是1850年由哲爾瓦（P.Gervais）提出的，并為1885年國際地質大會正式通過。

全新世時間短，沉積物厚度小，但分布范圍廣。由于距今時代短，可應用幾種有效的年代測定方法，因此，其地層劃分比較詳細、精確。全新世與更新世的界限，以第四紀冰期一次亞冰期結束、氣候轉暖為標志，因此又稱為冰后期。全新世氣候有輕微波動。海面變化與氣候相一致，冰后期海面迅速上升，到距今11000年上升到－60米位置。距今6000年海面已接近現(xiàn)今位置，其后僅有輕微的變化。全新世時，人類已進入現(xiàn)代人階段。

全新世的氣候變化與人類社會的發(fā)展有密切的關系，因此詳細研究全新世的氣候和環(huán)境變化至關重要。研究全新時氣候變化的主要材料包括高緯度和高海拔冰芯，湖泊沉積物紀錄，樹輪，石筍及其他洞穴沉積物，高沉積速率的深海沉積物等。

格陵蘭島的冰芯記錄提供了年紀分辨率的氣候變化，它顯示了自新仙女木事件（見passage 60）以后全新世氣溫很穩(wěn)定。但這種穩(wěn)定的氣溫變化受到越來越多的挑戰(zhàn)，有很多研究表明全新世的氣候變化同樣很明顯，并且呈現(xiàn)一定的周期性。

The?Greenland Ice Core Project?(GRIP) was a multinational?European?research project, organized through the?European Science Foundation.?Funding came from 8 nations (Belgium,?Denmark,?France,?Germany,?Iceland,?Italy,?Switzerland, and?United Kingdom), and from the?European Union.

The project ran from 1989 to 1995, with drilling seasons from 1990 to 1992.? GRIP successfully drilled a 3029-metre?ice core?to the bed of the?Greenland ice sheet?at Summit, Central?Greenland?from 1989 to 1992 at?72°34.74′N 37°33.92′W.

Studies of?isotopes?and various atmospheric constituents in the core have revealed a detailed record of?climate variability?reaching more than 100,000 years back in time. The results indicate that?Holocene?climate has been remarkably stable and have confirmed the occurrence of rapid climatic variation during the?last ice age?(the?Wisconsin). Delta-O-18 variations observed in the core part believed to date from the?Eemian Stage?have not been confirmed by other records?including the?NGRIP?core and are now believed not to represent climate events: the?interglacial?climate of Eemian Stage appears to have been as stable as the Holocene.