托福閱讀真題Official 49 Passage 1（六）

托福閱讀真題Official 49 Passage 1（六）

Ancient Coastlines

Information on past climates is primarily of relevance to archaeology because of what it tells us about the effects on the land and on the resources that people needed to survive.The most crucial effect of climate was on the sheer quantity of land available in each period,measurable by studying ancient coastlines.These have changed constantly through time,even in relatively recent periods,as can be seen from the Neolithic stone circle of Er Lannic,in Brittany,France(once inland but now half submerged on an island)or medieval villages in east Yorkshire,England,that have tumbled into the sea in the last few centuries as the North Sea gnaws its way westward and erodes the cliffs.Conversely,silts deposited by rivers sometimes push the sea farther back,creating new land,as at Ephesus in western Turkey,a port on the coast in Roman times but today some five kilometers inland.

Nevertheless,for archaeologists concerned with the long periods of time of the Paleolithic period there are variations in coastlines of much greater magnitude to consider.The expansion and contraction of the continental glaciers caused huge and uneven rises and falls in sea levels worldwide.When the ice sheets grew,the sea level would drop as water became locked up in the glaciers;when the ice melted,the sea level would rise again.Falls in sea level often exposed a number of important land bridges,such as those linking Alaska to northeast Asia and Britain to northwest Europe,a phenomenon with far-reaching effects not only on human colonization of the globe but also on the environment as a whole—the flora and fauna of isolated or insular areas were radically and often irreversibly affected.Between Alaska and Asia today lies the Bering Strait,which is so shallow that a fall in sea level of only four meters would turn it into a land bridge.When the ice sheets were at their greatest extent some 18,000 years ago(the glacial maximum),it is thought that the fall was about 120 meters,which therefore created not merely a bridge but a vast plain,1,000 kilometers from the north to the south,which has been called Beringia.The existence of Beringia(and the extent to which it could have supported human life)is one of the crucial pieces of evidence in the continuing debate about the likely route and date of human colonization of the New World.

The assessment of past rises and falls in sea level requires study of submerged land surfaces off the coast and of raised or elevated beaches on land.Raised beaches are remnants of former coastlines at higher levels relative to the present shoreline and visible,for instance,along the Californian coast north of San Francisco.The height of a raised beach above the present shoreline,however,does not generally give a straightforward indication of the height of a former sea level.In the majority of cases,the beaches lie at a higher level because the land has been raised up through isostatic uplift or tectonic movements.Isostatic uplift of the land occurs when the weight of ice is removed as temperatures rise,as at the end of an ice age;it has affected coastlines,for example,in Scandinavia,Scotland,Alaska,and Newfoundland during the postglacial period.Tectonic movements involve displacements in the plates that make up Earth’s crust;Middle and Late Pleistocene raised beaches in the Mediterranean are one instance of such movements.

Raised beaches often consist of areas of sand,pebbles,or dunes,sometimes containing seashells or piles of debris comprising shells and bones of marine animals used by humans.In Tokyo Bay,for example,shell mounds of the Jomon period(about 10,000 to 300 B.C.E.)mark the position of the shoreline at a time of maximum inundation by the sea(6,500–5,500 years ago),when,through tectonic movement,the sea was three to five meters higher in relation to the contemporary landmass of Japan than at present.Analysis of the shells themselves has confirmed the changes in marine topography,for it is only during the maximum phase that subtropical species of mollusc are present,indicating a higher water temperature.

Question 11 of 14

The word“comprising”in the passage is closest in meaning to

A.taken from

B.made up of

C.suggesting

D.covering

正確答案：B

題目詳解

題型分類：詞匯題

選項(xiàng)分析：

詞匯位于最后一段第一句，原句說上升沙灘常常由沙地、卵石或沙丘區(qū)域組成，有時(shí)還包含海貝或者殘骸堆，殘骸堆comprising人類用過的海洋動(dòng)物的貝殼和骨頭。根據(jù)常識，comprising前面的殘骸堆和后面人類用過的貝殼骨頭應(yīng)是包含關(guān)系，所以推測comprising是包含的意思，也可以說是made up of由……組成，B選項(xiàng)正確。

A選項(xiàng)：從……拿；

C選項(xiàng)：認(rèn)為是；

D選項(xiàng)：覆蓋，帶入原文均不符合語境。

Question 12 of 14

Which of the following can be inferred from paragraph 4 about Tokyo Bay?

A.The coastal land currently available is smaller than it was during the Jomon period.

B.The height of raised beaches around Tokyo Bay is a poor indicator of ancient sea levels.

C.The water temperature in Tokyo Bay is lower at present than it was during the Jomon period.

D.Tectonic movement during the Jomon period was not responsible for the formation of Tokyo Bay’s raised beaches.

正確答案：C

題目詳解

題型分類：推論題

原文定位：根據(jù)Tokyo Bay定位到最后一段第二句（原文高亮），這句講的是日本新石器時(shí)代的貝丘標(biāo)出了海水最高期海岸線的位置。當(dāng)時(shí)，經(jīng)過構(gòu)造運(yùn)動(dòng)，海洋與當(dāng)今的日本大陸相比要高出三到五米。文章最后一句講對東京港貝殼的分析，分析證實(shí)了海洋地形的變化，因?yàn)橹挥性谧罡咂谲涹w動(dòng)物的亞熱帶物種才會出現(xiàn)，這表明當(dāng)時(shí)的水溫更高。

選項(xiàng)分析：

C選項(xiàng)說現(xiàn)在的水溫與日本新石器時(shí)代相比更低is lower at present than it was…這與原文最后一句說那個(gè)時(shí)代有一個(gè)a higher water temperature是一致的。

A選項(xiàng)說與日本新石器時(shí)代相比，現(xiàn)有可用的海岸陸地is smaller與原文第二句新石器時(shí)代the sea was three to five meters higher海水更高矛盾。

B選項(xiàng)The height of raised beaches around Tokyo Bay屬于無中生有。最后一段只提到東京港shell mounds貝丘的位置和analysis of the shells對貝殼的分析，并沒有提到東京港附近上升沙灘的高度。

D選項(xiàng)說新石器時(shí)代的Tectonic movement構(gòu)造運(yùn)動(dòng)不是東京港上升沙灘形成的原因。原文第二句只提到構(gòu)造運(yùn)動(dòng)使得當(dāng)時(shí)海水比當(dāng)今日本大陸高，但沒有提到這與東京港上升沙灘形成的關(guān)系，屬于無中生有。

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