托福-练习十二及答案解析.doc

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1、托福-练习十二及答案解析(总分：38.00，做题时间：90 分钟)一、Passage 1(总题数：1，分数：13.00)Physical and Chemical Properties and ChangesSugar, water, and aluminum are different substances. Each substance has specific properties that do not depend on the quantity of the substance. Properties that can be used to identify or characte

2、rize a substance-and distinguish that substance from other substances-are called characteristic properties. They are subdivided into two categories: physical properties and chemical properties.The characteristic physical properties of a substance are those that identify the substance without causing

3、 a change in the composition of the substance. They do not depend on the quantity of substance. Color, odor, density, melting point, boiling point, hardness, metallic luster or shininess, ductility, malleability, and viscosity, are all characteristic physical properties. For example, aluminum is a m

4、etal that is both ductile and malleable. Another example of a physical property is water. Whether a small pan of water is raised to its boiling point or a very large kettle of water is raised to its boiling point, the temperature at which the water boils is the same value, 100 degrees C or 212 degre

5、es F. Similarly, the freezing point of water is 0 degrees C or 32 degrees F. These values are independent of quantity. （分数：13.00）(1).According to paragraph 1, what do physical properties and chemical properties have in common? _A. They are both used to create most of the substances.B. They include b

6、asic substances like sugar and water.C. They are classified as characteristic properties of substances.D. They change in proportion to the amount of the substance.（分数：1.00）A.B.C.D.(2).The word “pertain“ in the passage is closest in meaning to _.A. compare B. relate C. explain D. change（分数：1.00）A.B.C

7、.D.(3).The word “which“ in the passage refers to _.A. properties B. tendency C. density D. ratio（分数：1.00）A.B.C.D.(4).According to the passage, a carcinogen _.A. explodes under pressure B. conducts electricityC. causes cancer D. tarnishes in air（分数：1.00）A.B.C.D.(5).Which of the sentences below best e

8、xpresses the information in the highlighted statement in the passage? The other choices change the meaning or leave out important information.A. Properties that are classified as intensive identify the type of substance and the extent of it present in the surrounding matter.B. The quantity of a subs

9、tance influences its extensive properties, but the characteristics of the substance define the intensive properties.C. Where the intensive and extensive properties are found in substances is important in identifying their characteristics.D. Both intensive and extensive properties tend to have quanti

10、tative rather than qualitative characteristics present.（分数：1.00）A.B.C.D.(6).In paragraph 8, the author contrasts the concepts of physical and chemical changes by _.A. listing several types for each conceptB. providing clear definitions for themC. identifying the common characteristicsD. using a wax

11、candle as an example（分数：1.00）A.B.C.D.(7).The word “unique“ in the passage is closest in meaning to _.A. distinctive B. idealizedC. primary D. significant（分数：1.00）A.B.C.D.(8).What can be inferred about phase changes? _A. They are always chemical changes.B. They are sometimes physical changes.C. They

12、are dependent on extensive properties.D. They usually produce new substances.（分数：1.00）A.B.C.D.(9).The word “critical“ in the passage is closest in meaning to _.A. last B. importantC. difficult D. simple（分数：1.00）A.B.C.D.(10).According to the passage, the classification of characteristic properties as

13、 “physical“ or “chemical“ is determined by _.A. whether there has been a change in the structure of the substanceB. what happens when the quantity of the substance is increasedC. their classification as either extensive or intensive samplesD. the disappearance of a substance from one form to another

14、（分数：1.00）A.B.C.D.(11).All of the following are mentioned as characteristic physical properties EXCEPT _.A. dissolving in waterB. carrying an electrical chargeC. resisting continuous flowD. decomposing when heated（分数：1.00）A.B.C.D.(12).Look at the four squares, , , and （分数：1.00）A.B.C.D.(13).Directions

15、: Complete the table by matching the phrases on the left with the headings on the right. Select the appropriate answer choices and drag them to the characteristic properties to which they refer. TWO of the answer choices will NOT be used. This question is worth 4 points.Physical Properties_Chemical

16、Properties_Answer ChoicesA. Color of the substanceB. Reaction in an acidC. Decomposition in heatD. Temperature at which it boilsE. The tendency to shineF. The inclination to tarnishG. The shape of the substanceH Toxic if swallowed or inhaledI The relative amount in nature（分数：1.00）填空项 1:_二、Passage 2(

17、总题数：1，分数：12.00)The Evolution of the PhotofitSecurity technology: A new type of computerised photofit system takes a novel evolutionary approach to generating images of suspects. If you have ever tried to describe someones face in detail, you will understand why the “photofit“ composite images used b

18、y the police look so dodgy. In recent years, computerised “E-Fit“ systems have helped improve the accuracy of these images by allowing witnesses to choose from a wider range of facial features. But researchers at the University of Stirling in Scotland found that, despite these improvements, people s

19、till have a hard time constructing recognisable faces-especially if there is a delay of more than a few hours between seeing the face and generating the composite.The problem is that people tend to recognise faces as whole entities, rather than as separate features. So picking from a range of eyes,

20、noses and mouths is not necessarily the most suitable approach, says Charlie Frowd, a psychologist at the University of Stirling. Next year, however, British police are expected to begin trials of a new computerised system, called EvoFIT, developed by Dr. Frowd and his colleague Peter Hancock. It us

21、es an evolutionary approach, known as a genetic algorithm, to “evolve“ faces rather than piece them together.“The process is entirely non-verbal and takes a fraction of the normal time“, claims Dr. Frowd. A witness is shown an array of 60 different faces with random features. Having studied them clo

22、sely, the witness is asked to choose the six images that most closely resemble the person they are trying to describe. These six are then used to generate another set of 60, by switching featurees between some of the images and by making random changes to others. The witness is then asked to repeat

23、the task, whereupon a new batch of faces is generated, and so on. In evolutionary terms, this process is known as “genetic crossover and mutation“, and is a powerful way to search a large number of possibilities for a particular solution. By allowing the user to steer the selection process, the prog

24、ram is able to generate a good likeness for the original face after just a few cycles.In one of its early versions, EvoFIT was used by police in Northampton shire who were trying to catch a violent attacker. The attacker was never caught, but the senior investigating officer, Superintendent Paul Spi

25、ck, says the witness involved found the new software much quicker and easier to use than traditional E-Fit systems. It was also more accurate, the final image caused the witness visible distress when displayed. A further important advantage of EvoFIT over traditional composites is that an image can

26、be generated even if the witness can only provide a sketchy verbal description.The researchers have since made a number of further improvements to their system and are now in the process of commercializing it in partnership with ABM, a British firm which supplies police forces with photofit, one of

27、the leading computerized composite systems. The images are more realistic, and the system can generate three-quarter angle views of the face, which are easier to distinguish than direct frontal views, says Dr. Frowd.His team has also found that by combining the images generated by different witnesse

28、s, or even from a single witness, it is possible to get an even better likeness. This could be particularly useful when multiple witnesses come forward and the police are unsure which of the images they produce is the most accurate. In the latest version, witnesses are given a selection of face shap

29、es to choose from before facial features are added. （分数：12.00）(1).The word “composite“ in paragraph i is closest in meaning to _.A. mixture B. compose C. find D. system（分数：1.00）A.B.C.D.(2).The word “dodgy“ in paragraph 1 could best be replaced by _.A. evasive B. competitiveC. urgently D. unlike（分数：1

30、.00）A.B.C.D.(3).Why does the author mention “especially if there is a delay of more than a few hours.“ in paragraph 1? _A. Tend to have a hard time constructing recognizable faces.B. Tend to have a hard time telling people.C. Tend to have a hard time helping police.D. Try to resemble people.（分数：1.00

31、）A.B.C.D.(4).According to the passage, which of the following is true? _A. Faces are more often to be remembered as whole entities.B. Faces are not likely to be remembered as whole entities.C. Faces are more likely to be recognized.D. It can piece the facial features together based on witnesses desc

32、riptions.（分数：1.00）A.B.C.D.(5).Which sentence below best expresses the essential information in the highlighted sentence in paragraph 3? Incorrect choices change the meaning in important ways or leave out essential information.A. We can only find one particular solution in particular term, which we c

33、all “genetic revolutionary change“.B. It is difficult for us to find particular features and tell the faces because of “genetic crossover and mutation“.C. We have no idea to switch features between some of the images and by making random changes to others in evolutionary terms.D. We can search a lar

34、ge number of the features and resolve difficuties in evolutionary terms, which we call “genetic revolutionary change“.（分数：1.00）A.B.C.D.(6).According the passage, which of the following is true? _A. EvoFIT will have to address three questions though it looks promising so far.B. EvoFIT will have to ad

35、dress two questions though it looks promising so far.C. EvoFIT will have to address four questions though it looks promising so far.D. EvoFIT will have to address one question though it looks promising so far.（分数：1.00）A.B.C.D.(7).The word “its“ in paragraph 4 refers to _.A. EvoFIT B. photofit C. per

36、son D. attacker（分数：1.00）A.B.C.D.(8).The writer mentions a number of advantages of EvoFIT in paragraph 4 EXCEPT _.A. the user doesnt have to steer the selection processB. its a powerful way to search a large number of possibilities for a particular solutionC. it is quick and accurate in generating a

37、good likeness for the original faceD. an image can be generated even if the witness can only provide a sketchy verbal description（分数：1.00）A.B.C.D.(9).According to paragraph 4, what are the improvements that EvoFIT researchers have made to the system except? _A. Giving witnesses a selection of face s

38、hapes to choose from before facial features are added.B. Generating facial features after several rounds of selections.C. Combining the images generated by different witnesses or even from a single witness.D. Generating three-quarter angle views of the face.（分数：1.00）A.B.C.D.(10).Look at the four squ

39、ares, , , and （分数：1.00）A.B.C.D.(11).The word “contaminate“ in paragraph 8 could best be replaced by _.A. make unforgettable B. make cleanC. make large D. make impure（分数：1.00）A.B.C.D.(12).Directions: Complete the table below about how EvoFIT works in detail in the passage. This question is worth 3 po

40、ints.Genetic crossover and mutationStep 1_Step 2_Step 3_Step 4_Step 5_Answer ChoicesA. Ask the witness to choose the six images that closely resemble the person they try to describe.B. Combine the results of different witnesses.C. Switch features between some of the selected images or make random ch

41、anges to others.D. Add facial features to the selected face shapes.E. Ask the witness to repeat the task and generate a new batch of faces.F. Show the witness an array of 60 different faces with random features.G. Ask the witness to decide the face shapes that they have in memory.H Use the selected

42、six images to generate another set of 60 and repeat the cycle.（分数：1.00）填空项 1:_三、Passage 3(总题数：1，分数：13.00)The Rosetta StoneThings were not going well for Ptolemy V, king of Egypt in the second century B. C. He was not one of the all-powerful Egyptian pharaohs who had ruled for many centuries. The you

43、ng king was one of the Ptolemaic pharaohs who were of Greek heritage, descendants of a ruler put in place by Alexander the Great when he conquered Egypt in the fourth century B. C. The reign of Ptolemy V was a time of civil unrest and foreign incurious, and the king was unpopular. It was time for a

44、public-relations campaign. The priests of the king wrote a short history of the kings family, described his accomplishments, and explained his future plans. This message was written on stone tablets in demotic Egyptian for the common people, in Egyptian hieroglyphs for the priests, and in Greek for

45、the ruling class. Thus, it was written in two languages but in three scripts. These tablets were posted all over Egypt.Almost two thousand years later, in 1799, the French army, led by Napoleon Bonaparte, was occupying Egypt. Several years earlier, Napoleons army had defeated the British army near C

46、airo and had taken over the country. However, the British fleet had destroyed the French navy and there was no way for the French soldiers to return home. During this “extended vacation“, French military engineers strengthened existing defensive positions. In the port town of Rosetta (now known as E

47、I-Rashid), the French were rebuilding an old fort when Captain Pierre-Francois Bouchard discovered an irregularly shaped slab made of dark granite (often misidentified as basalt) with three types of writings on it in three distinct bands. Besides military forces, Napoleon had also brought scientists

48、 and scholars with him. The Rosetta Stone, as it became known, was turned over to them. They quickly realized that the three scripts contained the same message.They translated the Greek quickly but could not understand the other two scripts.In 1801, the French were forced to surrender. Under the ter

49、ms of the Treaty of Alexandria, the British claimed the artifacts that the French had found during their occupation. The French tried to smuggle the Rosetta Stone out of Egypt in a small boat but failed. The stone was brought to London and presented to the British Museum. On the back of the stone is the painted message, “Captured by the British Army in Egypt in 1801“.It was th