托福-练习十六及答案解析.doc

1、托福-练习十六及答案解析(总分：30.00，做题时间：90 分钟)一、Passage 1(总题数：3，分数：10.00)1 The cells of a plant are organized into three tissue systems: dermal, vascular, and ground tissue. Each tissue system is continuous throughout the plants body. The specific characteristics of each tissue, however, are different in the dif

2、ferent organs of the plant.2 The dermal tissue system is the “skin“ of the plant. The dermal system, or epidermis, is a single layer of cells covering the entire body of the plant. The main function of the epidermis is to protect the plant. The epidermis also has specialized chamcteristics for the p

3、articular organs it covers. For example, the epidermis of leaves and stems has a waxy coating that helps the plant conserve water, and the epidermal cells near the tips of the plants roots help the plant absorb water and nutrients from the soil.3 The second tissue system-the vascular system-is the t

4、ransportation system for water and nutrients. Vascular tissue also helps to support the plants structure. The third system- the ground tissue-makes up the bulk of a plant, filling all of the spaces between the dermal and vascular tissue systems. Ground tissue functions in photosynthesis, storage, an

5、d support.（分数：3.00）(1).How are the three tissue systems of a plant similar to each other?（分数：1.00）A.They all continue throughout the plants body.B.They all have a protective waxy coating.C.They all consist of a single layer of cells.D.They all perform the same bodily functions.(2).Which of the follo

6、wing statements best describes the plants epidermis?（分数：1.00）A.It helps the plant to stand upright.B.It transports water and nutrients.C.It covers the plants entire body.D.It is found only in young plants.(3).Which type of tissue does a plants body mainly consist of?.（分数：1.00）A.DermalB.VascularC.Epi

7、dermisD.Ground1 By the decades just before the Civil War of the 1860s, the Southern states had developed an economic culture distinct from that of the North. The economy of the South depended largely on two things: cotton and slave labor. Because of the rising demand for cotton from the mills of Eng

8、land, and the invention of the cotton gin in 1793, the cotton production of the South increased tremendously. In 1790, cotton output had been 9,000 bales a year, but by the 1850s, output had soared to five million bales. In the South, cotton was “king.“ The most readily available source of labor was

9、 the institution of slavery. Thus, cotton and slavery became interdependent, and the South grew more reliant on both.2 This was in sharp contrast to the North, where farming was becoming more mechanized and diversified. Northern farmers would boast of improvements in the form of new roads, railways,

10、 and machinery, and of the production of a variety of crops. In the South, however, farmers bought laborers instead of equipment, and a mans social status depended on the number of slaves he owned. The economic differences between the two regions would ultimately lead to armed conflict and the socia

11、l restructuring of the South.（分数：3.00）(1).Why did the Southern output of cotton greatly increase between 1790 and 1850?（分数：1.00）A.Southern farmers invested in transportation.B.Mills in England demanded more cotton.C.The South was trying to dominate the North.D.Southern cotton was superior to Norther

12、n cotton.(2).What was associated more with the North in the period discussed?（分数：1.00）A.Farm machineryB.Slave laborC.Military serviceD.Reliance on one crop(3).The author argues that the Civil War between the North and the South（分数：1.00）A.was a conflict over control of the cotton tradeB.began in 1790

13、 and lasted almost seventy yearsC.was largely the result of economic differencesD.forced the South to produce different crops1 Play is common to the young of most mammals. Some birds play, but it is rare in cold-blooded animals such as fish and reptiles. Why some animals play, and others do not, is

14、not entirely understood, but the most playful-such as dolphins and monkeys-are also the most intelligent and sociable. Play may seem something of a puzzle. Not only is it apparently unproductive, but it also places the participant at risk of being surprised by predators. However, there must be a goo

15、d reason for play. The most widely held scientific explanation is that play allows the social behaviors of the species to be explored and learned. Other benefits include physical exercise and the learning of survival skills such as hunting. A kitten that grows up separated from other kittens becomes

16、 both a social misfit and a poor hunter, largely because it is deprived of play.2 Kittens start playing when they are about three weeks old. Early play consists of mock attacks with the mother and littermates, clearly previewing the territorial behavior of adult life. As the kittens grow older, more

17、 elaborate play patterns develop. At four weeks they can wrestle. The sideways leap and the pounce may be learned by the fifth week. By six weeks they can chase and leap on each other with reasonable accuracy. Kittens stalk, chase, and fall over each other. They recognize these patterns as being pla

18、yful, even though the same signals in adult life may have a more serious meaning.（分数：4.00）(1).The author makes the point that the most playful animals are（分数：1.00）A.cold-blooded animalsB.highly intelligent and sociableC.easily surprised by predatorsD.not a subject of scientific study(2).The author m

19、entions dolphins and monkeys as examples of（分数：1.00）A.rare speciesB.fish and reptilesC.playful animalsD.predators(3).According to paragraph 1, a kitten that has no contact with other kittens will（分数：1.00）A.have to play with toysB.be afraid of peopleC.exercise more than other kittensD.not learn socia

20、l and hunting skills(4).According to paragraph 2, which of the following statements is true?（分数：1.00）A.The mock attacks of young kittens disappear by the age of six weeks.B.Actions that are playful in kittens convey a different meaning in adult cats.C.Territorial behavior in kittens is a sign of dev

21、elopmental problems.D.Kittens and human children share many of the same play patterns.二、Passage 2(总题数：3，分数：10.00)1 Erik Erikson believed that personality development is a series of turning points, which he described in terms of the tension between desirable qualities and dangers. He emphasized that

22、only when the positive qualities outweigh the dangers does healthy psychosocial development take place.2 An important turning point occurs around age six. A child entering school is at a point in development when behavior is dominated by intellectual curiosity and performance. He or she now learns t

23、o win recognition by producing things. The child develops a sense of industry. The danger at this stage is that the child may experience feelings of inadequacy or inferiority. If the child is encouraged to make and do things, allowed to finish tasks, and praised for trying, a sense of industry is th

24、e result. On the other hand, if the childs efforts are unsuccessful, or if they are criticized or treated as bothersome, a sense of inferiority is the result. For these reasons, Erikson called the period from age six to eleven Industry vs. Inferiority.（分数：3.00）(1).According to Eriksons theory, what

25、desirable quality should develop in a child who is six to eleven years old?（分数：1.00）A.A liking for schoolB.A feeling of inadequacyC.An ability to finish tasksD.A sense of industry(2).According to Eriksons theory, what will happen if a childs efforts are criticized?（分数：1.00）A.The child will dislike h

26、is teacher.B.The child will avoid other children.C.The child will try harder to win recognition.D.The child will feel inferior.(3).Industry vs. Inferiority is an example of（分数：1.00）A.the tension between a positive quality and a dangerB.a personality disorder in childrenC.the difference between a chi

27、ld of six and a child of elevenD.an educational strategy1 In the storytelling traditions of West Africa, the tiny rabbit appears frequently as a rascal who teases or plays jokes on bigger animals. In one story, Mr. Rabbit tricks Mr. Elephant and Mrs. Whale into a tug of war with each other. Such tal

28、es about Mr. Rabbit continue to be part of the oral traditions of the Wollof people of Senegal.2 The African-American folktales of the U.S. South also feature a trickster rabbit in the character of Brer Rabbit. In his American incarnation, Brer Rabbit uses his wits to overcome circumstances and even

29、 to enact playful revenge on his larger, stronger adversaries, Brer Fox, Brer Wolf, and Brer Bear. Although he is not always successful, Brer Rabbits efforts make him both a folk hero and a friendly comic figure. Joel Chandler Harris, a journalist in Georgia, had heard old men tell Brer Rabbit tales

30、 by the fireside when he was a young boy. Harris wrote down and published many of the stories, popularizing them for the general public.3 A folklorist named Alcee Fortier recorded very similar versions of the same stories in southern Louisiana, where the rabbit character was known as Compair Lapin i

31、n Creole French. More recently, the rabbit has enjoyed another incarnation as the cartoon character Bugs Bunny-a rascally rabbit who causes trouble, tricks the hunter, and always gets the final word.（分数：3.00）(1).What trait belongs to the rabbit character in tales of West African origin?（分数：1.00）A.St

32、orytelling abilityB.Very keen eyesightC.Ability to fool othersD.Strong, athletic body(2).How did a wide audience of people know about the Brer Rabbit stories?（分数：1.00）A.They studied the oral traditions of West Africa.B.They heard old men tell the stories by the fireside.C.They read the stories publi

33、shed by a journalist.D.They listened to recordings from southern Louisian(3).What do Brer Rabbit, Compair Lapin, and Bugs Bunny have in common?（分数：1.00）A.All are cartoon characters.B.All play tricks on others.C.All save others from trouble.D.All speak Creole Frenc1 A hot spot is a giant underground

34、caldron of molten rock in one of the worlds many volcanically active areas. The steamy geysers, thermal pools, and mud pots of Yellowstone National Park owe their origins to hot spots.2 Annually, more than 200 geysers erupt in Yellowstone, making this one of the most interesting places in the world

35、for geologists. Over 100 geysers lie within the Upper Geyser Basin, a one-square-mile area near Old Faithful, the most famous geyser in the world. The Yellowstone hot spot was created around ten million years ago, and the center of the park is still volcanically active, with molten rock only a mile

36、or two beneath the Earths surface.3 When rain and melted snow seep down through tiny cracks in the Earth, the water eventually reaches underground chambers of lava-heated rock. The rock heats the water, and the boiling water and steam often make their way back up to the surface in the form of a geys

37、er, a thermal pool, or a mud pot.4 In a geyser, water trapped in an underground chamber heats up beyond the boiling point and forms steam. Since steam takes up 1,500 times more space than water, pressure builds up, eventually forcing the superheated water to burst to the surface as a geyser. A therm

38、al pool is formed when the water from the hot spot reaches the surface before cooling off. If the water does not make it all the way to the surface, steam and gases may dissolve rocks and form a bubbling mud pot instead.（分数：4.00）(1).Where do hot spots occur?（分数：1.00）A.In rocky regions near the equat

39、orB.Below the ground near active volcanoesC.About a mile above a volcanos craterD.In the center of ancient volcanoes(2).According to the passage, why is Yellowstone National Park an interesting place for geologists?（分数：1.00）A.There are 100 square miles of hot spots.B.Over 200 geysers erupt there eac

40、h year.C.There are more than 100 different kinds of geysers.D.More than 200 types of rock are found ther(3).How do hot spots contribute to the formation of geysers?（分数：1.00）A.Hot spots melt all of the snow falling into a volcanos crater.B.Water is trapped in an underground chamber and cannot escape.

41、C.Hot rocks create boiling water, steam, and pressure underground.D.Water from hot spots rises to the surface before it cools of(4).When do mud pots form?（分数：1.00）A.When steam and gases dissolve rocks near the surfaceB.When underground water exceeds the boiling pointC.When snow melts in Yellowstones

42、 geyser basinsD.When superheated water bursts to the surface三、Passage 3(总题数：3，分数：10.00)1 Most matter exists as compounds-combinations of atoms or oppositely charged ions of two or more different elements held together in fixed proportions by chemical bonds. Compounds are classified as organic or ino

43、rganic. Organic compounds contain atoms of the element carbon, usually combined with itself and with atoms of one or more other elements such as hydrogen, oxygen, nitrogen, sulfur, phosphorus, and chlorine. Many materials important to us-food, vitamins, blood, skin, cotton, wool, paper, oil, plastic

44、s-are organic compounds.2 Larger and more complex organic compounds, called polymers, consist of a number of basic structural units linked together by chemical bonds. Important organic polymers include carbohydrates, proteins, and nucleic acids. Carbohydrates, such as the complex starches in rice an

45、d potato plants, are composed of a number of simple sugar molecules. Proteins are produced in plant and animal cells by the linking of different numbers and sequences of about twenty different structural units known as amino acids. Most animals, including humans, can manufacture about ten of these a

46、mino acids in their cells, but the other ten, called essential amino acids, must be obtained from food in order to prevent protein deficiency. Nucleic acids are composed of hundreds to thousands of four different units called nucleotides linked together in different numbers and sequences. DNA and RN

47、A in plant and animal cells are nucleic acids.（分数：3.00）(1).Which of the following statements applies to all organic compounds?（分数：1.00）A.They are composed of carbon and one or more other elements.B.They contain atoms of the seven most abundant elements.C.They have stronger chemical bonds than inorga

48、nic compounds do.D.They are produced by linking several simple sugar molecules.(2).Carbohydrates, proteins, and nucleic acids are types of（分数：1.00）A.elementsB.inorganic compoundsC.polymersD.amino acids(3).Why is it important for humans to obtain some amino acids from food?（分数：1.00）A.Without certain

49、amino acids, humans store too much fat.B.Organically grown food is the only source of amino acids.C.Sufficient amino acids are necessary for DNA production.D.Humans cells cannot make the ten essential amino acids.1 By the 1840s, British North America had developed a vibrant commercial economy based on its abundant natural resources and a growing international trade. Fish, furs, timber, and grains represented over 90 percent of all economic activity. The oldest of the resource commodities, fish, was traditionally associated with Newfoundland and continued to domina