第8套描写春天的片段
Attempts at Determining Earth's Age
Since the dawn of civilization,people have been curious about the age of Earth.In addition,we have not been satisfied in being able to state merely the relative geologic age of a rock or fossil.Human curiosity demands that we know actual age in years. Geologists working during the nineteenth century understood that if they were to discover the actual age of Earth or of particular rock bodies,they would have to concentrate on natural process that continue at a constant rate and that also leave some sort of tangible record in the rocks.Evolution is one such process,and geologist Charles Lyell(1797-1875)recognized this.By comparing the amount of evolution exhibited by marine mollusks during the Tertiary Period with the amount that had occurred since then,Lyell estimated that80million years had elapd since the beginning of the Tertiary Period.He came astonishingly clo to the mark,since it was actually about65million years.However,for older quences of evolutionary development,estimates bad on rates of evolution were difficult,and not only becau of missing parts in the fossil record.Rates of evolution for many orders of plants and animals were not well understood.
1.The word tangible in the passage is clost in meaning to
A.physical
C.significant
买油翁D.helpful
2..It can be inferred from paragraph2that Charles Lyell bad his study of the marine mollusk fossils on which of the following assumptions
A.The Tertiary Period was parated into divisions of time that were equal in length.
B.Mollusks lived under rocks in the a during the Tertiary period.
平面设计自学C.Evolution of mollusks proceeded at a uniform rate over time.
D.Mollusks have evolved less rapidly with the passing of time.
3..The word quences in the passage is clost in meaning to
A.obrvations
B.ns
C.ries
D.categories
4..According to paragraph2,Lyell's strategy for estimating geologic dates was not very accurate for periods before the Tertiary Period partly becau
A.marine mollusks did not evolve until the Tertiary Period
B.fossil records of the very distant past are incomplete
C.there was not much agreement about how to identify or categorize earlier eras
D.the duration of previous geologic periods was difficult to determine
In another【attempt】,geologists reasoned that if rates of deposition could be determined for dimentary rocks,they might be able to estimate the time required for deposition of a given thickness of strata,or rock layers.Similar reasoning suggested that one could estimate total elapd
geologic time by dividing the average thickness of diment transported annually to the oceans into the total thickness of dimentary rock that had ever been deposited in the past.Unfortunately,such estimates did not adequately account for past differences in rates of dimentation or loss to the total ction of strata during episodes of erosion.Also,some very ancient diments were no longer recognizable,having been converted to igneous and metamorphic rocks in the cour of mountain building.Estimates of Earth's total age bad on dimentation rates ranged from as little as a million to over a billion years.
5..The phra another attempt in the passage refers to
6..The word converted in the passage is clost in meaning to
A.added
B.changed
7..According to paragraph3,all of the following were problems with the calculation of Earth's age using the study of dimentary rocks EXCEPT
A.the inconsistency of dimentation rates over time
B.the effect of geologic process on dimentary rock
C.the expansion of some dimentary rocks due to Earth's internal heat
D.the loss of an unknown number of dimentary layers due to erosion
Yet another scheme for approximating Earth's age had been propod in1715by Sir Edmund Halley(1656-1742),who name we associate with the famous comet. Halley surmid that the ocean formed soon after the origin of the planet and therefore would be only slightly younger than th
e age of the solid Earth.He reasoned that the original ocean was not salty and that subquently salt derived from the weathering of rocks was brought to the a by streams.Thus,if one knew the total amount of salt dissolved in the ocean and the amount added each year,it might be possible to calculate the ocean's age.In1899,Irish geologist John Joly(1857-1933)attempted the calculation.From information provided by gauges placed at the mouths of streams, Joly was able to estimate the annual increment of salt to the oceans.Then,knowing
the salinity of ocean water and the approximate volume of water,he calculated the amount of salt already held in solution in the oceans.An estimate of the age of the ocean was obtained by dividing the total salt in the ocean by the rate of salt added each year.Beginning with esntially nonsaline oceans,it would have taken about90 million years for the oceans to reach their prent salinity,according to Joly.The figure,however,was off the currently accepted mark of4.54billion by a factor of50, largely becau there was no way to account accurately for recycled salt and salt incorporated into clay minerals deposited on the a floors.Even though in error, Joly's calculations clearly supported tho geologists who insisted on an age for Earth far in excess of a few million years.The belief in Earth's immen antiquity was also supported by Darwin,Huxley,and other evolutionary biologists,who saw the need for time in the hundreds of millions of years to accomplish the organic evolution apparent in the fossil record.
8..The word approximating in the passage is clost in meaning to
A.thinking about
C.estimating
D.demonstrating
9..The word subquently in the passage is clost in meaning to
A.later
B.furthermore
C.evidently
D.accidentally
10..According to paragraph4,John Joly's calculations were founded on all of the following EXCEPT
A.knowing how salty the ocean water is
手提式灭火器B.estimating how much salt enters the ocean each year
C.accounting for the amount of salt that is recycled
四片叶子的三叶草D.figuring the volume of water contained in the ocean
11..According to paragraph4,in which of the following ways could Joly's estimate of Earth's age be considered significant
A.It proved that Halley's idea about the age of the ocean was fairly accurate.
B.It indicated that Earth was much older than some scientists had claimed.
C.It was favored by the majority of scientists at the end of the nineteenth century.
D.It was the basis for much modern rearch into the salinity of the ocean.
12..The author mentions Darwin,Huxley,and other evolutionary biologists in order to
A.provide evidence that Joly's calculations inspired scientists working on other lines of scientific inquiry
B.support the claim that all of the leading scientists of the time believed that Earth
was just over90million years old
C.argue that Joly's calculations would have been more exact if he had collaborated with experts in other fields
D.provide examples of scientists who believed the age of Earth to be greater than just
a few million years,like Joly,in order to account for their findings
13..Look at the four squares that indicate where the following ntence could be added to the passage.
More fundamentally,Lyell's evolutionary approach is intrinsically limited becau Earth existed long before life and evolution began.
Where would the ntence best fit Click on a square to add the ntence to the passage.
Geologists working during the nineteenth century understood that if they were to discover the actual age of Earth or of particular rock bodies,they would have to concentrate on natural process that continue at a constant rate and that also leave some sort of tangible record in the rocks.Evolution is one such process,and geologist Charles Lyell(1797-1875)recognized this.【】By comparing the amount of evolution exhibited by marine mollusks during the Tertiary Period with the amount that had occurred since then,Lyell estimated that80million years had elapd since the beginning of the Tertiary Period.He came astonishingly clo to the mark,since it was actually about65million years.【】However,for older quences of evolutionary development,estimates bad on rates of evolution were difficult,and not only becau of missing parts in the fossil record.【】Rates of evolution for many orders of plants and animals were not well understood.【】
14..Drag your choices to the spaces where they belong.To review the passage,click on View Text.
Answer Choices
A.It was not until the nineteenth century that attempts were made to determine the relative geologic age of rocks and fossils.
B.In the nineteenth century,scientists made a number of important,but unsuccessful, attempts to calc
ulate Earth's age from the record of various natural process.
C.Charles Lyell made a good estimate of the age of the Tertiary Period from the fossil record,but his method could not be extended to earlier geological periods.
D.Darwin and Huxley supported the accuracy of John Joly's calculation of Earth's age becau it agreed with their view of how long evolution had been in progress.
E.Attempts were made to calculate Earth's age from the thickness of surviving dimentary rock and from the current level of the oceans'salinity.
F.Earth's true age,4.54billion years,was determined by combining data from the geological and fossil records.
The Upper Paleolithic Revolution
The transition from the historical period known as the Middle Paleolithic to the Upper Paleolithic around40to35thousand years ago(kya)reprents one of the major developments in the prehistory of humankind.【A】The basic features of this transition include more versatile stone implements and the u of antler,bone,and ivory for tools,figurative art,music,and personal decoration.【B】So strikin
g were the strides in human achievement during this period that it is sometimes referred to as the Upper Paleolithic Revolution.【C】
dealing
【D】Until recently it had been argued that the Upper Paleolithic Revolution was an archaeological phenomenon found only in Eurasia.The apparent lack of equivalent evidence in other regions suggested that a fundamental change had occurred in human intellectual development around40kya in Europe.The recent discovery in the Blombos Cave in South Africa of a block of decorated ochre and then ts of shell beads,dated to around77kya,opened up the debate.This supports other evidence of more versatile stone implements and bone tools found in Africa from the same period. Now the Upper Paleolithic Revolution is being en as simply the most visible example of the evolving process of modern human behavior that had been developing over a much longer timescale.
1..Why does the author mention a a block of decorated ochre and ts of shell beads
A.To help make the point that archaeologists regard artistic creations as the highest kind of human achievement
B.To illustrate how the discovery of certain objects makes the discovery of certain other objects more
likely
C.To give some of the evidence that has changed archaeologists'thinking about human intellectual development
To help explain why archaeologists have been slow to recognize the importance of certain evidence available to them
2..How far back in time do the origins of the more versatile stone implements and bone tools found in Africa go
满意度测评
A.To around40kya
B.To around77kya
C.To the time of the Upper Paleolithic Revolution
D.To a time before modern human behavior had begun to evolve
This rais two further questions.First,what was happening to the human cognitive process during th
结婚典礼主持词e40,000years or so between the creations in the Blombos Cave and the flourishing of human creativity in Europe around35kya,and cond,was climate change a component Climate change is associated with the sudden occurrence of creative activity in Europe at the beginning of the Upper Paleolithic.
3..The word equivalent in the passage is clost in meaning to
