1、托福分类模拟题 17及答案解析(总分：100.00，做题时间：90 分钟)一、READING(总题数：0，分数：0.00)二、TEST 1-1(总题数：1，分数：42.00)Zebra Mollusks? Small, freshwater zebra mollusks have been invading America“s freshwater lakes and rivers for more than fifteen years. The shellfish are native to Russia, the Balkans, and Poland and were originall
2、y found in the areas of the Ural River and the Black, Caspian, and Azov Seas in the 1700s. By the late 1700s and early 1800s, they had spread to many parts of Europe because of the numerous canals. In 1824 these mussels were discovered in Great Britain. Today, they have infested most of Western Euro
3、pe as well as the Scandinavian countries, Ireland and Italy. Zebra mollusks were transported to North America in 1988 in the ballast water of a transatlantic freighter and were discharged into Lake St. Clair, an inland lake in Michigan which connects Lake Erie and Lake Huron. Within four years the m
4、ollusks had infested one lake. Within ten years, more than one hundred lakes had become home for these invaders. Today, these invasive mussels have established themselves in all of the Great Lakes, other inland lakes in Michigan, and the basins of most navigable rivers in the eastern United States i
5、ncluding the Mississippi, Tennessee, Ohio, and Hudson Rivers. Their presence has also recently been detected in the Missouri River basin. ? Zebra mollusks, which get their name from the striped pattern of their shells, are prolific breeders. Females can produce between 30,000 and one million eggs ea
6、ch year. During their planktonic larval stage, young zebra mollusks are the size of a human hair and appear invisible to the human eye and the tiny shellfish can live and feed in many different aquatic habitats, and they can move easily and swiftly in water currents and can drift many miles before s
7、ettling. Adult zebra mollusks live about five years and can survive in fresh water at levels deeper than twenty feet. Once the mollusks reach their adult stage they attach themselves to hard objects in water. Boats, buoys, piers, and fishing gear can be their victims as well as clams, crayfish, turt
8、les and other creatures living in the water. Zebra mollusks also attach themselves to each other to form huge colonies. ? Environmentally, zebra mollusks can be a threat. When they attach themselves to watercraft, the mollusks can cling to the hull or motor or any part of the boat which is immersed
9、in the water. As a result, boats can overheat, have increased drag, and show damaged engine cooling systems. Piers, navigational buoys, and other structures can sink under the weight of the attached mollusks or suffer deterioration and long term damage from the attachment of the shellfish. Many muni
10、cipalities have been required to redesign the intake systems for their city water supplies because mollusks have clogged the intake pipelines. Other communities have resorted to chemicals to treat and prevent zebra mollusk problems. The mollusks can threaten native wildlife and marine life and upset
11、 ecosystems. Marine life is also severely affected by zebra mollusks when the mollusks attach themselves to slow moving animals such as turtles and crayfish or to clams and mussels which are found naturally in fresh water lakes. When the zebra mollusks attach themselves to an object in large numbers
12、, the mollusks are said to be “colonizing.“ Colonizing interferes with the object“s ability to feed itself and its growth, movement, respiration, and reproduction abilities. Despite problems caused by the mollusks, they also provide benefits to polluted bodies of water. As they filter water, they di
13、gest animals and algae that provide food for other fish and animals. The benefit of the filtering process, however, is that water clarity in infested lakes and rivers increases dramatically. These tiny shellfish also provide food for many native birds and fish but they cannot be eaten in amounts gre
14、at enough to control the mollusk population. Zebra mollusks help provide more healthy environments for aquatic plants, and in some inland lakes and rivers the smallmouth bass population has increased because the additional aquatic plants have provided feeding and nursery areas for young fish. ? Envi
15、ronmental agencies, local communities, and inland lake associations are working diligently to protect people and waters from the threat of the zebra mollusks. Once the mollusks become established in bodies of water, eradication is difficult, if not impossible, because the creatures seem to be oblivi
16、ous to all but the harshest chemicalschemicals which can kill other plant and wild life. Because zebra mollusks can survive out of the water for as long as five days in cool, humid climates, boaters, fishing enthusiasts, and all lake lovers need to learn how not to transmit the invaders, in larvae a
17、nd adult form, between bodies of water. Glossaryfreighter: a large ship or airplane that is designed for carrying freight breeder: people who breed animals or plants buoy: a floating object that is used to show ships and boats where they can go and to warn them of danger（分数：42.00）(1).Based on the in
18、formation in paragraph 1, which of the following best explains the term zebra mollusks?（分数：3.00）A.small, freshwater shellfish native to North AmericaB.invasive mussels which have established themselves in inland watersC.invasive shellfish establishing themselves in salt watersD.small, freshwater mus
19、sels confined to the Balkans, Russia, and Poland(2).The word ballast in the passage is closest in meaning to（分数：3.00）A.weightedB.crushed stoneC.metal containersD.hold of a ship(3).Based upon the information in paragraph 2 and paragraph 3, what can be inferred about the mollusks mentioned in paragrap
20、h 1?（分数：3.00）A.The problems they cause can be corrected.B.Their benefits outweigh the problems they cause.C.They may be a continuing problem.D.Environmentally, they are not a problem.(4).According to paragraph 5, which is true about zebra mollusks?（分数：3.00）A.They are helpful to people.B.They only ca
21、use harm to watercraft and structures located in water.C.They like warm, dry days and cool, dry evenings.D.The threat of zebra mollusks may not be able to be eradicated.(5).In paragraph 2, the author states that the water currents（分数：3.00）A.provide an aquatic habitat for adult mollusksB.permit the y
22、oung mollusks to move easily and quickly to their new habitatsC.provide swift movement for adult mollusksD.protect boats and piers from adult mollusks(6).According to paragraph 1, what can be inferred about the spread of zebra mollusks?（分数：3.00）A.South America has been spared the infestation of zebr
23、a mollusks.B.Mollusks will continue to infest waters of the world unless eradicated.C.The mollusks discovered in Britain were canal mollusks.D.Western United States has been spared the infestation of zebra mollusks.(7).What is the problem in eradicating the zebra mollusks according to the last parag
24、raph?（分数：3.00）A.the use of chemicalsB.the ability of mollusks to live in or out of water for extended timeC.the easy transportability of mollusksD.all of the above(8).Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices c
25、hange the meaning in important ways or leave out essential information. Within ten years, more than one hundred lakes had become home for these invaders.（分数：3.00）A.Rivers have not been invaded by the mollusks.B.The word “invaders“ should not be used for these mollusks.C.Inland lakes are polluted.D.Z
26、ebra mollusks are easily widespread.(9).In paragraph 3, why does the author explain that mollusks can cling to boats?（分数：3.00）A.to point out that mollusks can cling to any hard surfaceB.to argue that environmentalists will know where to look for mollusksC.to make readers aware that the mobility of m
27、ollusks can become a threatD.to suggest that mollusks form attractive colonies on boats as well as on piers and docks(10).The word discharged in the passage is closest in meaning to（分数：3.00）A.firedB.dismissedC.separatedD.released(11).The word dramatically in the passage is closest in meaning to（分数：3
28、.00）A.increasinglyB.significantlyC.adequatelyD.minimally(12).Which of the following statements more accurately reflects the author“s opinion about environmental problems associated with zebra mollusks?（分数：3.00）A.Environmental agencies will be able to solve the zebra mollusk problem.B.Communities are
29、 unable to solve the problems associated with mollusks.C.Lake associations are working with river associations to eradicate mollusks.D.Everybody needs to combine efforts to solve the problems associated with zebra mollusks.(13).Look at the four squares that indicate where the following sentence coul
30、d be added to the passage. Because they are filter feeders, zebra mollusks can filter about a quart or liter of water each day while feeding on algae. Where would the sentence best fit? Click on a square to add the sentence to the passage.（分数：3.00）(14).Directions: An introductory sentence for a brie
31、f summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they may express ideas that are not presented in the passage or are minor ideas in the pass
32、age. This question is worth 2 points. Drag your answer choices to the spaces where they belong. To remove an answer choice, click on it. To review the passage, click on View Text: Zebra mollusks have arrived in huge numbers to infest American lakes and waterways. Answer Choices:（分数：3.00）A.The world“
33、s lakes and waterways are infected with mollusks.B.Lake clarity should take priority over municipal water supplies.C.Ocean-going freighters need stricter regulation to avoid problems such as zebra mollusks.D.By population increase, mollusks provide benefits to fresh water lakes.E.Eradicating mollusk
34、s with harsh chemicals may cause other environmental problems.F.“Colonizing“ can harm structures placed in inland lakes and rivers.三、TEST 1-2(总题数：1，分数：30.00)The Navajo PeopleA total of 300,000 people are currently counted as belonging to the formerly vast Navajo nation. The Navajos, an indigenous No
35、rth American tribe scatterd over vast areas in Utah, New Mexico, California and Arizona, originally belong to the Athabaskan people which fan out from west-central Canada up to the American Southwest. According to oral Navajo traditions, this ethnic group split away from the larger Apaches clan some
36、time during the early 1500s before migrating further down towards the Mexican border, where it eventually settled. Navajos were first mentioned as a separate ethnicity around 1620, when the Spanish settlers make reference to the “Apachu de Navajo“ when speaking of the tribes inhabiting the Chama riv
37、er in the vicinity of Santa Fe. This documents quite a massive migration from the Great Plains even though an accurate timeline of this population movement is difficult to establish due to the Navajo“s austere lifestyle. These early people tended to construct rather modest dwellings and wield a smal
38、l number of simple tools and goods. Thus, they clothed themselves in tanned and greased cowhides that they also used to erect winter hogans to protect themselves against inclement weather. During the bison hunting season, the tent would easily be dissembled and all belongings, including poles, were
39、loaded on travoises pulled by Plains dogs. These traction animals were able to haul along an astonishing load of up to fifty pounds at a rate of two to three miles an hour. These simple features of the Navajo lifestyle have long posed quite a challenge for archaeologists forced to work with a limite
40、d amount of data when piecing together the Navajo history. Nevertheless, it has been established that the Navajo forged strong commercial bonds with the Pueblo people of the Rio Grande valley in the midsts of the 16th century, with whom they traded bison meat, hides and material for stone tools in e
41、xchange for cotton and maize. Later in the 17th century, the Navajos occupied the abandoned Pueblo territories as relentless pressure from Spanish colonists and the intermittent warfare with neighboring tribes intensified. The contact with the Pueblos and their other allies, the Utah and Comanche pe
42、ople, as well as the inevitable cultural clash with the European invaders brought about a change in the Navajo lifestyle. Primarily nomadic hunting gatherers, they later resorted to a more sedentary way of living and took up pottery, weaving and farming, while nevertheless preserving their own tradi
43、tional values and system of beliefs. The Navajos penchant for simplicity is, for example, most evident in their woven blankets, which display symmetrical geometrical patterns in red yarn. The typical Germantown rugs are undoubtebly the finest pieces of textile art in Native American history. The sam
44、e clean and unadorned lines are evident in the Navajo silversmithing technique, which favors the insertion of turquoise gem stones. Navajo spiritual and religious practices share that nation“s purity of thought. They are designed chiefly to restore health, balance and harmony to the individual. It i
45、s believed that sickness is the result of contamination with impure elements as a result of the violation of certain taboos. These may include contact with lightening-struck elements, exposure to taboo animals such as snakes, or contact with the dead. Navajo warriors thus undergo a Blessing Way Cere
46、mony before being sent off to war, as well as an Enemy Way Ceremony which allows them to cope with post-traumatic stress disorders. Such sacred ceremonies last an average of four days and require the presence of a large number of relatives and friends to ensure their success. Furthermore, they are t
47、o be performed according to a rigid set of rules by a trained medicine man, a Hatili, should they yield the desired effect. 1 The preferred location of any religious ceremony is the hogan, which is a sacred place as it was built according to the instructions of the First Coyote, the mythological anc
48、estor of the Navajo. 2 The ceremonies are accompanied by numerous blessings and chants that reveal the rich heritage and profound spirituality of this indigenous tribe. 3 They pay tribute to a matriarchal society, in which female dwellers are the only members allowed to own livestock or land. 4 By c
49、ustom, a newly married Navajo male will move into his bride“s hogan, and any accumulated goods will be inherited along the matrimonial line. This sharp contrast to the currently accepted patriarchal system must be the reason for the Navajo“s inherent non-aggressive and pacifist behavior. Glossaryhogan: a Navajo Indian dwelling constructed of earth and branches and covered with mud or sod travois: a transport device, formally used by the Plains Indians, consisting of two poles joined by a frame and drawn by an animal（分数：30.00）(1).The phrase ethnic
