Passage 1

　　In choosing a method for determining climatic condi-

　　tions that existed in the past， paleoclimatologists invoke

　　four principal criteria. First， the material-rocks， lakes，

　　vegetation， etc.-on which the method relies must be

　　（ 5 ）widespread enough to provide plenty of information，

　　since analysis of material that is rarely encountered will

　　not permit correlation with other regions or with other

　　periods of geological history. Second， in the process of

　　formation， the material must have received an environ-

　　（10） mental signal that reflects a change in climate and that

　　can be deciphered by modern physical or chemical

　　means. Third， at least some of the material must have

　　retained the signal unaffected by subsequent changes in

　　the environment. Fourth， it must be possible to deter-

　　（15） mine the time at which the inferred climatic conditions

　　held. This last criterion is more easily met in dating

　　marine sediments， because dating of only a small

　　number of layers in a marine sequence allows the age of

　　other layers to be estimated fairly reliably by extrapola-

　　（20） tion and interpolation. By contrast， because sedimenta-

　　tion is much less continuous in continental regions， esti-

　　mating the age of a continental bed from the known

　　ages of beds above and below is more risky.

　　One very old method used in the investigation of past

　　（25） climatic conditions involves the measurement of water

　　levels in ancient lakes. In temperate regions， there are

　　enough lakes for correlations between them to give us a

　　reliable picture. In arid and semiarid regions， on the

　　other hand， the small number of lakes and the great

　　（30） distances between them reduce the possibilities for corre-

　　lation. Moreover， since lake levels are controlled by rates

　　of evaporation as well as by precipitation， the interpreta-

　　tion of such levels is ambiguous. For instance， the fact

　　that lake levels in the semiarid southwestern United

　　（35） States appear to have been higher during the last ice age

　　than they are now was at one time attributed to

　　increased precipitation. On the basis of snow-line eleva-

　　tions， however， it has been concluded that the climate

　　then was not necessarily wetter than it is now， but rather

　　（40） that both summers and winters were cooler， resulting in

　　reduced evaporation.

　　Another problematic method is to reconstruct former

　　climates on the basis of pollen profiles. The type of vege-

　　tation in a specific region is determined by identifying

　　（45） and counting the various pollen grains found there.

　　Although the relationship between vegetation and

　　climate is not as direct as the relationship between

　　climate and lake levels， the method often works well in

　　the temperate zones. In arid and semiarid regions in

　　（50） which there is not much vegetation， however， small

　　changes in one or a few plant types can change the

　　picture dramatically， making accurate correlations

　　between neighboring areas difficult to obtain.

　　1. Which of the following statements about the

　　difference between marine and continental

　　sedimentation is supported by information in the

　　passage？

　　（A） Data provided by dating marine sedimentation is

　　more consistent with researchers' findings in

　　other disciplines than is data provided by dating

　　continental sedimentation.

　　（B） It is easier to estimate the age of a layer in a

　　sequence of continental sedimentation than it

　　is to estimate the age of a layer in a sequence

　　of marine sedimentation.

　　（C） Marine sedimentation is much less widespread

　　than continental sedimentation.

　　（D） Researchers are more often forced to rely on

　　extrapolation when dating a layer of marine

　　sedimentation than when dating a layer of

　　continental sedimentation.

　　（E） Marine sedimentation is much more continuous

　　than is continental sedimentation.

　　2. Which of the following statements best describes the

　　organization of the passage as a whole？

　　（A） The author describes a method for determining past

　　climatic conditions and then offers specific

　　examples of situations in which it has been used.

　　（B） The author discusses the method of dating marine

　　and continental sequences and then explains how

　　dating is more difficult with lake levels than with

　　pollen profiles.

　　（C） The author describes the common requirements of

　　methods for determining past climatic conditions

　　and then discusses examples of such methods.

　　（D） The author describes various ways of choosing a

　　material for determining past climatic conditions

　　and then discusses how two such methods have

　　yielded contradictory data.

　　（E） The author describes how methods for determining

　　past climatic conditions were first developed and

　　then describes two of the earliest known methods.

　　3. It can be inferred from the passage that

　　paleoclimatologists have concluded which of the

　　following on the basis of their study of snow-line

　　elevations in the southwestern United States？

　　（A） There is usually more precipitation during an ice age

　　because of increased amounts of evaporation.

　　（B） There was less precipitation during the last ice age

　　than there is today.

　　（C） Lake levels in the semiarid southwestern United

　　States were lower during the last ice age than they

　　are today.

　　（D） During the last ice age， cooler weather led to lower

　　lake levels than paleoclimatologists had previously

　　assumed.

　　（E） The high lake levels during the last ice age may have

　　been a result of less evaporation rather than more

　　precipitation.

　　4. Which of the following would be the most likely topic

　　for a paragraph that logically continues the passage？

　　（A） The kinds of plants normally found in arid regions

　　（B） The effect of variation in lake levels on pollen

　　distribution

　　（C） The material best suited to preserving signals of

　　climatic changes

　　（D） Other criteria invoked by paleoclimatologists when

　　choosing a method to determine past climatic

　　conditions

　　（E） A third method for investigating past climatic

　　conditions

　　5. The author discusses lake levels in the southwestern

　　United States in order to

　　（A） illustrate the mechanics of the relationship between

　　lake level， evaporation， and precipitation

　　（B） provide an example of the uncertainty involved in

　　interpreting lake levels

　　（C） prove that there are not enough ancient lakes with

　　which to make accurate correlations

　　（D） explain the effects of increased rates of evaporation

　　on levels of precipitation

　　（E） suggest that snow-line elevations are invariably

　　more accurate than lake levels in determining rates

　　of precipitation at various points in the past

　　6. It can be inferred from the passage that an

　　environmental signal found in geological material

　　would not be useful to paleoclimatologists if it

　　（A） had to be interpreted by modern chemical means

　　（B） reflected a change in climate rather than a long-

　　term climatic condition

　　（C） was incorporated into a material as the material was

　　forming

　　（D） also reflected subsequent environmental changes

　　（E） was contained in a continental rather than a marine

　　sequence

　　7. According to the passage， the material used to determine

　　past climatic conditions must be widespread for which

　　of the following reasons？

　　Ⅰ。Paleoclimatologists need to make comparisons

　　between periods of geological history.

　　Ⅱ。 Paleoclimatologists need to compare materials that

　　have supported a wide variety of vegetation.

　　Ⅲ。 Paleoclimatologists need to make comparisons with

　　data collected in other regions.

　　（A） Ⅰ only

　　（B） Ⅱ only

　　（C） Ⅰ and Ⅱ only

　　（D） Ⅰ and Ⅲ only

　　（E） Ⅱ and Ⅲ only

　　8. Which of the following can be inferred from the passage

　　about the study of past climates in arid and semiarid

　　regions？

　　（A） It is sometimes more difficult to determine past

　　climatic conditions in arid and semiarid regions than

　　in temperate regions.

　　（B） Although in the past more research has been done on

　　temperate regions， paleoclimatologists have

　　recently turned their attention to arid and semiarid

　　regions.

　　（C） Although more information about past climates can

　　be gathered in arid and semiarid than in temperate

　　regions， dating this information is more difficult.

　　（D） It is difficult to study the climatic history of arid and

　　semiarid regions because their climates have tended

　　to vary more than those of temperate regions.

　　（E） The study of past climates in arid and semiarid

　　regions has been neglected because temperate

　　regions support a greater variety of plant and animal

　　life.

　　Passage 2

　　Australian researchers have discovered electroreceptors

　　（sensory organs designed to respond to electrical fields）

　　clustered at the tip of the spiny anteater's snout. The

　　researchers made this discovery by exposing small areas of

　　（5） the snout to extremely weak electrical fields and recording

　　the transmission of resulting nervous activity to the brain.

　　While it is true that tactile receptors， another kind of

　　Sensory organ on the anteater's snout， can also respond to

　　electrical stimuli， such receptors do so only in response to

　　（10） electrical field strengths about 1，000 times greater than

　　those known to excite electroreceptors.

　　Having discovered the electroreceptors， researchers are

　　now investigating how anteaters utilize such a sophisticated

　　sensory system. In one behavioral experiment， researchers

　　（15） successfully trained an anteaters to distinguish between

　　two troughs of water， one with a weak electrical field

　　and the other with none. Such evidence is consistent with

　　researchers' hypothesis that anteaters use electroreceptors

　　to detect electrical signals given off buy prey； however，

　　（20） researchers as yet have been unable to detect electrical

　　signals emanating from termite mounds， where the favorite

　　food of anteaters live. Still， researchers have observed

　　anteaters breaking into a nest of ants at an oblique angle

　　and quickly locating nesting chambers. This ability quickly

　　（25） to locate unseen prey suggests， according to the researchers，

　　that the anteaters were using their electroreceptors to

　　locate the nesting chambers.

　　1. According to the passage， which of the following is a characteristic that distinguishes electroreceptors from tactile receptors？

　　（A） The manner in which electroreceptors respond to electrical stimuli

　　（B） The tendency of electroreceptors to be found in clusters

　　（C） The unusual locations in which electroreceptors are found in most species.

　　（D） The amount of electrical stimulation required to excite electroreceptors

　　（E） The amount of nervous activity transmitted it the brain by electroreceptors when they are excited

　　2. Which of the following can be inferred about experiment described in the first paragraph？

　　（A） Researchers had difficulty verifying the existence of electroreceptors in the anteater because electroreceptors respond to such a narrow range of electrical field strengths.

　　（B） Researchers found that the level of nervous activity in the anteater's brain increased dramatically as the strength of the electrical stimulus was increased.

　　（C） Researchers found that some areas of the anteater's snout were not sensitive to a weak electrical stimulus.

　　（D） Researchers found that the anteater's tactile receptors were more easily excited by a strong electrical stimulus than were the electroreceptors.

　　（E） Researchers tested small areas of the anteater's snout in order to ensure that only electroreceptors were responding to the stimulus.

　　3. The author of the passage most probably discussed the function of tactile receptors （lines 7-11） in order to

　　（A） eliminate and alternative explanation of anteater's response to electrical stimuli

　　（B） highlight a type of sensory organ that has a function identical to that of electroreceptors

　　（C） point out a serious complication in the research on electroreceptors in anteaters

　　（D） suggest that tactile receptors assist electroreceptors in the detection of electrical signals

　　（E） introduce a factor that was not addressed in research on electroreceptors in anteaters

　　4. Which of the following can be inferred about anteaters from the behavioral experiment mentioned in the second paragraph？

　　（A） They are unable to distinguish between stimuli detected by their tactile receptors.

　　（B） They are unable to distinguish between the electrical signals emanating from termite mounds and those emanating from ant nests.

　　（C） They can be trained to recognize consistently the presence of a particular stimulus.

　　（D） They react more readily to strong than to weak stimuli.

　　（E） They are more efficient at detecting stimuli in a controlled environment than in a natural environment.

　　5. The passage suggests that researchers mentioned in the second paragraph who observed anteaters break into a nest of ants would most likely agree with which of the following statements？

　　（A） The event they observed provides conclusive evidence that anteaters use their electroreceptors to locate unseen prey.

　　（B） The event they observed was atypical and may not reflect the usual hunting practices of anteaters.

　　（C） It is likely that the anteaters located the ants' nesting chambers without the assistance of electroreceptors.

　　（D） Anteaters possess a very simple sensory system for use in locating prey.

　　（E） The speed with which the anteaters located their prey is greater than what might be expected on the basis of chance alone.

　　6. Which of the following， if true， would most strengthen the hypothesis mentioned in lines 17-19？

　　（A） Researchers are able to train anteaters to break into an underground chamber that is emitting a strong electrical signal.

　　（B） Researchers are able detect a weak electrical signal emanating from the nesting chamber of an ant colony.

　　（C） Anteaters are observed taking increasingly longer amounts of time to locate the nesting chambers of ants.

　　（D） Anteaters are observed using various angles to break into nests of ants.

　　（E） Anteaters ate observed using the same angle used with nests of ants to break into the nests of other types of prey.

　　Passage 3

　　Most economists in the United States seem

　　captivated by the spell of the free market. Conse-

　　quently， nothing seems good or normal that does

　　not accord with the requirements of the free market.

　　（ 5 ）A price that is determined by the seller or， for

　　that matter， established by anyone other than the

　　aggregate of consumers seems pernicious. Accord-

　　ingly， it requires a major act of will to think of

　　price-fixing （the determination of prices by the

　　（10） seller） as both “normal” and having a valuable

　　economic function. In fact， price-fixing is normal

　　in all industrialized societies because the indus-

　　trial system itself provides， as an effortless conse-

　　quence of its own development， the price-fixing

　　（15） that it requires. Modern industrial planning

　　requires and rewards great size. Hence，

　　a comparatively small number of large firms will

　　be competing for the same group of consumers.

　　That each large firm will act with consideration of

　　（20） its own needs and thus avoid selling its products

　　for more than its competitors charge is commonly

　　recognized by advocates of free-market economic

　　theories. But each large firm will also act with

　　full consideration of the needs that it has in

　　（25） common with the other large firms competing for

　　the same customers. Each large firm will thus

　　avoid significant price-cutting， because price-

　　cutting would be prejudicial to the common interest

　　in a stable demand for products. Most economists

　　（30） do not see price-fixing when it occurs because

　　they expect it to be brought about by a number of

　　explicit agreements among large firms； it is not.

　　Moreover， those economists who argue that

　　allowing the free market to operate without inter-

　　（35） ference is the most efficient method of establishing

　　prices have not considered the economies of non-

　　socialist countries other than the United states.

　　These economies employ intentional price-fixing，

　　usually in an overt fashion. Formal price-fixing

　　（40） by cartel and informal price-fixing by agreements

　　covering the members of an industry are common-

　　place. Were there something peculiarly efficient

　　about the free market and inefficient about price-

　　fixing， the countries that have avoided the first

　　（45） and used the second would have suffered drastically

　　in their economic development. There is no indica-

　　tion that they have.

　　Socialist industry also works within a frame-

　　work of controlled prices. In the early 1970's，

　　（50） the Soviet Union began to give firms and industries

　　some of the flexibility in adjusting prices that a

　　more informal evolution has accorded the capitalist

　　system. Economists in the United States have

　　hailed the change as a return to the free market.

　　（55） But Soviet firms are no more subject to prices

　　established by a free market over which they

　　exercise little influence than are capitalist firms；

　　rather， Soviet firms have been given the power to

　　fix prices.

　　1. The primary purpose of the passage is to

　　（A） refute the theory that the free market plays a

　　useful role in the development of industrialized

　　societies

　　（B） suggest methods by which economists and members

　　of the government of the United States can

　　recognize and combat price-fixing by large firms

　　（C） show that in industrialized societies price-fixing and

　　the operation of the free market are not only

　　compatible but also mutually beneficial

　　（D） explain the various ways in which industrialized

　　societies can fix prices in order to stabilize the free

　　market

　　（E） argue that price-fixing， in one form or another， is an

　　inevitable part of and benefit to the economy of any

　　industrialized society

　　2. The passage provides information that would answer

　　which of the following questions about price-fixing？

　　Ⅰ。What are some of the ways in which prices can be

　　fixed？

　　Ⅱ。 For what products is price-fixing likely to be more

　　profitable than the operation of the free market？

　　Ⅲ。Is price-fixing more common in socialist industrialized

　　societies or in nonsocialist industrialized societies？

　　（A） Ⅰonly

　　（B） Ⅲ only

　　（C） Ⅰand Ⅱonly

　　（D） Ⅱand Ⅲ only

　　（E） Ⅰ，Ⅱ，and Ⅲ

　　3. The author's attitude toward “Most economists in the

　　United States“（line 1） can best be described as

　　（A） spiteful and envious

　　（B） scornful and denunciatory

　　（C） critical and condescending

　　（D） ambivalent but deferential

　　（E） uncertain but interested

　　4. It can inferred from the author's argument that a price

　　fixed by the seller “seems pernicious”（line 7） because

　　（A） people do not have confidence in large firms

　　（B） people do not expect the government to

　　regulate prices

　　（C） most economists believe that consumers as a

　　group should determine prices

　　（D） most economists associate fixed prices with

　　communist and socialist economies

　　（E） most economists believe that no one group

　　should determine prices

　　5. The suggestion in the passage that price-fixing in

　　industrialized societies is normal arises from the

　　author's statement that price-fixing is

　　（A） a profitable result of economic development

　　（B） an inevitable result of the industrial system

　　（C） the result of a number of carefully organized

　　decisions

　　（D） a phenomenon common to industrialized and

　　nonindustrialized societies

　　（E） a phenomenon best achieved cooperatively by

　　government and industry

　　6. According to the author， price-fixing in nonsocialist

　　countries is often

　　（A） accidental but productive

　　（B） illegal but useful

　　（C） legal and innovative

　　（D） traditional and rigid

　　（E） intentional and widespread

　　7. According to the author， what is the result of the Soviet

　　Union's change in economic policy in the 1970's？

　　（A） Soviet firms show greater profit.

　　（B） Soviet firms have less control over the free market.

　　（C） Soviet firms are able to adjust to technological

　　advances.

　　（D） Soviet firms have some authority to fix prices.

　　（E） Soviet firms are more responsive to the free market.

　　8. With which of the following statements regarding the

　　behavior of large firms in industrialized societies

　　would the author be most likely to agree？

　　（A） The directors of large firms will continue to

　　anticipate the demand for products.

　　（B） The directors of large firms are less interested in

　　achieving a predictable level of profit than in

　　achieving a large profit.

　　（C） The directors of large firms will strive to reduce the

　　costs of their products.

　　（D） Many directors of large firms believe that the

　　government should establish the prices that will be

　　charged for products.

　　（E） Many directors of large firms believe that the price

　　charged for products is likely to increase annually.

　　9. In the passage， the author is primarily concerned with

　　（A） predicting the consequences of a practice

　　（B） criticizing a point of view

　　（C） calling attention to recent discoveries

　　（D） proposing a topic for research

　　（E） summarizing conflicting opinions

　　KEYS

　　Passage 1： ECEEB DDA

　　Passage 2： DCACE B

　　Passage 3： EACCB EDAB