1、托福-38 及答案解析(总分：146.05，做题时间：90 分钟)一、BREADING/B(总题数：0，分数：0.00)二、BPART /B(总题数：1，分数：10.40)Reading “Symbiotic Relationships“ Symbiosis is a close, long-lasting physical relationship between two different species. In other words, the two species are usually in physical contact and at least one of them der
2、ives some sort of benefit from this contact. There are three different categories of symbiotic relationships: parasitism, commensalism, and mutualism. Parasitism is a relationship in which one organism, known as the parasite, lives in or on another organism, known as the host, from which it derives
3、nourishment. Generally, the parasite is much smaller than the host. Although the host is harmed by the interaction, it is generally not killed immediately by the parasite, and some host individuals may live a long time and be relatively little affected by their parasites. Some parasites are much mor
4、e destructive than others, however. UNewly established parasite/host relationships are likely to be/U Umore destructive than those that have a long evolutionary history./U With a longstanding interaction between the parasite and the host, the two species generally evolve in such a way that they can
5、accommodate one another. It is not in the parasites best interest to kill its host. If it does, it must find another. Likewise, the host evolves defenses against the parasite, often reducing the harm done by the parasite to a level the host can Utolerate./U Parasites that live on the surface of thei
6、r hosts are known as Uectoparasites./U Fleas, lice, and some molds and mildews are examples of ectoparasites. Many other parasites, like tapeworms, malaria parasites, many kinds of bacteria, and some fungi, are called Uendoparasites/U because they live inside the bodies of their hosts. A tapeworm li
7、ves in the intestines of its host where it is able to resist being digested and makes use of the nutrients in the intestine. Even plants can be parasites. Mistletoe is a flowering plant that is parasitic on trees. It establishes itself on the surface of a tree when a bird transfers the seed to the t
8、ree. It then grows down into the water-conducting tissues of the tree and uses the water and minerals it obtains from these tissues to support its own growth. （分数：10.40）(1).The word Uderives/U in the passage is closest in meaning to A. requests B. pursues C. obtains D. rejects（分数：0.80）A.B.C.D.(2).Th
9、e word it in the passage refers to A. host B. organism C. parasite D. relationship（分数：0.80）A.B.C.D.(3).The word relatively in the passage is closest in meaning to A. comparatively B. routinely C. adversely D. frequently（分数：0.80）A.B.C.D.(4).Which of the sentences below best expresses the information
10、in the highlighted statement in the passage? The other choices change the meaning or leave out important information. A. A parasite is less likely to destroy the host when it attaches itself at first. B. Parasites that have lived on a host for a long time have probably done a lot of damage. C. The m
11、ost destructive phase for a host is when the parasite first invades it. D. The relationship between a parasite and a host will evolve over time. （分数：0.80）A.B.C.D.(5).D. The relationship between a parasite and a host will evolve over time. 5. The word Utolerate/U in the passage is closest in meaning
12、to A. permit B. oppose C. profit D. avoid （分数：0.80）A.B.C.D.(6).According to paragraph 3, how do ectoparasites survive? A. They live in mold and mildew on their hosts. B. They digest food in the intestines of their hosts. C. They live on the nutrients in their bacterial hosts. D. They inhabit the out
13、side parts of their hosts.（分数：0.80）A.B.C.D.(7).Which of the following is mentioned as an example of a commensal relationship? A. Orchids B. Mistletoe C. Ants D. Fungus（分数：0.80）A.B.C.D.(8).The word Uactually/U in the passage is closest in meaning to A. frequently B. initially C. really D. usually（分数：
14、0.80）A.B.C.D.(9).In paragraph 7, why does the author use the example of the Acacia tree? A. To demonstrate how ants survive by living in trees B. To explain how two species can benefit from contact C. To show the relationship between plants and animals D. To present a problem that occurs often in na
15、ture（分数：0.80）A.B.C.D.(10).According to paragraph 8, how does bacteria affect beans and clover? A. It causes many of the plants to die. B. It limits the growth of young plants. C. It supplies nitrogen to the crops. D. It infects the roots with harmful nodules.（分数：0.80）A.B.C.D.(11).Look at the four sq
16、uares m that show where the following sentence could be inserted in the passage. They live on the feathers of birds or the fur of animals. Where could the sentence best be added? Click on a square to insert the sentence in the passage. A. Square . B. Square . C. Square . D. Square .（分数：0.80）A.B.C.D.
17、(12).In which of the following chapters would this passage most probably appear? A. Environment and Organisms B. Pollution and Policies C. Human Influences on Ecosystems D. Energy Resources（分数：0.80）A.B.C.D.(13).Directions: Complete the table by matching the phrases on the left with the headings on t
18、he right. Select the appropriate answer choices and drag them to the type of relationship to which they refer. TWO of the answer choices will NOT be used. This question is worth 4 points. To delete an answer choice, click on it. To see the passage, click on View Text. Answer Choices A. One species b
19、enefits and the other is not harmed. B. Both species benefit from their contact. C. Both species harm each other in the relationship. D. One species is harmed while the other species benefits. E. Often one of the species is destroyed by the relationship. F. During evolution, this relationship may be
20、come symbiotic. G. Both species may require their relationship for survival. (H) In this relationship, the host may evolve defenses to avoid harm. (I) Both species are more successful when they form this relationship. Parasitic _ _ _ Commensal _ _ _ Mutualistic _（分数：0.80）填空项 1:_三、BPART /B(总题数：2，分数：1
21、9.60)Reading 2 “Civilization“ Between 4000 and 3000 B.C., significant technological developments began to transform the Neolithic towns. The invention of writing enabled records to be kept, and the use of metals marked a new level of human control over the environment and its resources. Already befo
22、re 4000 B.C., craftspeople had discovered that metal-bearing rocks could be heated to liquefy metals, which could then be cast in molds to produce tools and weapons that were more useful than stone instruments. Although copper was the first metal to be utilized in producing tools, after 4000 B.C. cr
23、aftspeople in western Asia discovered that a combination of copper and tin produced bronze, a much harder and more durable metal than copper. Its widespread use has led historians to speak of a Bronze Age from around 3000 to 1200 B.C., when bronze was increasingly replaced by iron. At first, Neolith
24、ic settlements were hardly more than villages. But as their inhabitants mastered the art of farming, they gradually began to give birth to more complex human societies. As wealth increased, such societies began to develop armies and to build walled cities. By the beginning of the Bronze Age, the con
25、centration of larger numbers of people in the river valleys of Mesopotamia and Egypt was leading to a whole new pattern for human life. As we have seen, early human beings formed small groups that developed a simple culture that enabled them to survive. As human societies grew and developed greater
26、complexity, a new form of human existencecalled civilization-came into being. A civilization is a complex culture in which large numbers of human beings share a number of common elements. UHistorians have/U Uidentified a number of bas c character st cs of civilization, most of which are/U Uevident i
27、nthe Mesopotamian and Egyptian civilizations./U These include (1) an urban revolution; cities became the focal points for political, economic, social, cultural, and religious development; (2) a distinct religious structure; the gods were deemed crucial to the communitys success, and professional pri
28、estly classes, as stewards of the gods property, regulated relations with the gods; (3) new political and military structures; an organized government bureaucracy arose to meet the administrative demands of the growing population while armies were organized togain land and power; (4) a new social st
29、ructure based on economic power; while kings and an upper class of priests, political leaders, and warriors dominated, there also existed large groups of free people (farmers, artisans, craftspeople) and at the very bottom, socially, a class of slaves; (5) the development of writing; kings, priests,
30、 merchants, and artisans used writing to keep records; and (6) new forms of significant artistic and intellectual activity, such as monumental architectural structures, usually religious, occu- pied a Uprominent/U place in urban environments. Why early civilizations developed remains difficult to ex
31、plain. Since civilizations developed independently in India, China, Mesopotamia, and Egypt, can general causes be identified that would explain why all of these civilizations emerged? A number of possible explanations of the beginning of civilization have been suggested. A theory of challenge and re
32、sponse maintains that challenges forced human beings to make efforts that resulted in the rise of civilization. Some scholars have adhered to a material explanation. Material forces, such as the growth of food surpluses, made possible the specialization of labor and development of large communities
33、with bureaucratic organization. （分数：10.40）(1).Which of the following is the best definition of a civilization? A. Neolithic towns and cities B. Types of complex cultures C. An agricultural community D. Large population centers（分数：0.80）A.B.C.D.(2).The word Uits/U in the passage refers to A. copper B.
34、 bronze C. metal D.iron（分数：0.80）A.B.C.D.(3).According to paragraph 2, what happens as societies become more prosperous? A. More goods are produced. B. Walled cities are built. C. Laws are instituted. D. The size of families increased.（分数：0.80）A.B.C.D.(4).The word Uhardly/U in the passage is closest
35、in meaning to A. frequently B. likely C. barely D. obviously（分数：0.80）A.B.C.D.(5).Why does the author mention Neolithic towns in paragraph 2? A. To give an example of a civilization B. To explain the invention of writing systems C. To argue that they should be classified as villages D. To contrast th
36、em with the civilizations that evolved（分数：0.80）A.B.C.D.(6).According to paragraph 3, how was the class system structured? A. An upper class and a lower class B. Slaves, free people, and a ruling class C. A king, an army, and slaves D. Intellectuals and uneducated farmers and workers（分数：0.80）A.B.C.D.
37、(7).Which of the sentences below best expresses the information in the highlighted statement in the passage? The other choices change the meaning or leave out important information. A. Mesopotamian and Egyptian civilizations exhibit the majority of the characteristics identified by historians. B. Th
38、e characteristics that historians have identified are not found in the Egyptian and Mesopotamian cultures. C. Civilizations in Mesopotamia and Egypt were identified by historians who were studying the characteristics of early cultures. D. The identification of most historical civilizations includes
39、either Egypt or Mesopotamia on the list.（分数：0.80）A.B.C.D.(8).The word Ucrucial/U in the passage is closest in meaning to A. fundamental B. arbitrary C. disruptive D. suitable（分数：0.80）A.B.C.D.(9).The word Uprominent/U in the passage is closest in meaning to A. weak B. important C. small D. new（分数：0.8
40、0）A.B.C.D.(10).According to paragraph 4, how can the independent development of civilization in different geographic regions be explained? A. Scholars agree that food surpluses encouraged populations to be concentrated in certain areas. B. There are several theories that explain the rise of civiliza
41、tion in the ancient world. C. The model of civilization was probably carried from one region to another along trade routes. D. Historians attribute the emergence of early cities at about the same time as a coincidence.（分数：0.80）A.B.C.D.(11).All of the following are cited as reasons why civilizations
42、developed EXCEPT A. Religious practices unified the population. B. The management of water required organization. C. A major climate change made living in groups necessary. D. Extra food resulted in the expansion of population centers.（分数：0.80）A.B.C.D.(12).Look at the four squares that show where th
43、e following sentence could be inserted in the passage. Some historians believe they can be established. Where could the sentence best be added? Click on a square to insert the sentence in the passage. A. Square . B. Square . C. Square . D. Square .（分数：0.80）A.B.C.D.(13).Directions: An introduction fo
44、r a short summary of the passage appears below. Complete the summary by selecting the THREE answer choices that mention the most important points in the passage. Some sentences do not belong in the summary because they express ideas that are not included in the passage or they are minor points from
45、the passage. This question is worth 2 points. Certain qualities appear to define a civilization. _ _ _ Answer ChoicesA. Free citizens who work in professions for pay B. Bureaucracies for the government and armies C. Libraries to house art and written records D. A strategic location near rivers or th
46、e sea E. Organized religion, writing, and art F. A densely populated group with a class Structure（分数：0.80）填空项 1:_Reading 3 “Life in Our Solar System“ Although we can imagine life based on something other than carbon chemistry, we know of no examples to tell us how such life might arise and survive.
47、We must limit our discussion to life as we know it and the conditions it requires. The most important requirement is the presence of liquid water, not only as part of the chemical reactions of life, but also as a medium to transport nutrients and wastes within the organism. The water requirement Uau
48、tomatically/U eliminates many worlds in our solar system. The moon is airless, and although some data suggest ice frozen in the soil at its poles, it has never had liquid water on its surface. In the vacuum of the lunar surface, liquid water would boil away rapidly. Mercury too is airless and cannot have had liquid water on its surface for long periods of time. Venus has
