1、托福-22 及答案解析(总分：119.90，做题时间：90 分钟)一、READING(总题数：0，分数：0.00)二、Set 1(总题数：1，分数：13.00)Energy from Natural Gas1. Much of the world gets its energy from fossil fuel sources, including coal, oil, and natural gas, all of which were created millions of years ago.The process began with dead plant and animal mat
2、ter that collected and over time was buried deep within the earth. There, exposed to extreme pressure and temperatures, the carbon-based material underwent various chemical and physical changes. Some of it became coal, some oil, and some natural gas, depending on the exact conditions it was subjecte
3、d to.2. Natural gas is both invisible and odorless. During the first century of the fossil fuel era, it was disregarded as a worthless byproduct of coal and oil. However, people later discovered that it could also be a useful source of energy, and they set about trying to realize its potential. Its
4、use began to grow in the twentieth century and has increased rapidly within the last 40 years. Nowadays, natural gas is employed all over the world to heat homes, generate electricity, power factories, and even fuel vehicles.3. Because it was created through the same process as other fossil fuels, n
5、atural gas can often be retrieved from oil fields, something known as an associated source. Coal beds have similarly been known to yield natural gas. In addition, there are isolated deposits containing only gas that are referred to as non-associated sources. To access a subterranean natural gas pock
6、et, a hole is drilled down into it, just as in oil extraction. However, due to the gass lightness, it will rise to the surface on its own instead of having to be pumped out.4. The compound we know as natural gas is actually a composite of several different substances, the primary one being methane g
7、as. Each deposit has a unique makeup, but other common components of natural gas include propane, butane, and sulfur. Borrowing terms used in the description of oil, natural gas with a high sulfur content is called “sour“ while that with a low content is referred to as “sweet“ Regardless of the exac
8、t composition, natural gas must be refined to remove its impurities; when ready for use, it is nearly pure methane.5. Natural gas offers many advantages as a fuel source, the first and most important being that it is extremely clean burning. While oil and coal both have complex molecular structures,
9、 methanes is simple: one carbon atom surrounded by four atoms of hydrogen. The lack of excess particles translates into fewer waste byproducts during combustion. For example, all fossil fuels produce carbon dioxide when burned, but natural gas releases substantially less carbon dioxide than other fu
10、els. Given the major role of carbon dioxide in the acceleration of global warming, this is an important attribute. In addition, natural gas emits far less nitrogen and sulfur, which are key contributors to the smog that pollutes the air in metropolitan areas, as well as acid rain.6. The benefits of
11、natural gas extend far beyond its cleanliness. Since it contains fewer waste particles, its energy can be acquired with much more efficiency than that of the other fossil fuels, meaning a lower overall cost for the consumer. Another advantage is that natural gas is transported via underground pipeli
12、nes instead of by ships and trucks. Finally, natural gas is relatively plentiful and widespread. Geologists have identified extensive stores in Canada, the United States, Russia, the Middle East, and Australia, among other locations. （分数：13.00）(1).According to Paragraph 1, the oil, coal, and natural
13、 gas that exist todayA. remain mostly hidden.B. share similar origins.C. are found deep underground.D. can be hard to tell apart.（分数：1.00）A.B.C.D.(2).The phrase realize its potential in the passage is closest in meaning toA. recognize its success.B. exploit it.C. measure its capacity.D. manufacture
14、it.（分数：1.00）A.B.C.D.(3).In Paragraph 2, the author explains that natural gas useA. was delayed due to a lack of technology.B. has only recently become widespread.C. began late in the nineteenth century.D. has surpassed that of the other fossil fuels.（分数：1.00）A.B.C.D.(4).What can be inferred from Par
15、agraph 3 about the extraction of natural gas?A. It mainly occurs during the extraction of coal.B. There is the potential for large amounts of gas to be lost.C. It is a simpler process than the extraction of oil.D. Non-associated sources are preferred.（分数：1.00）A.B.C.D.(5).The word composite in the pa
16、ssage is closest in meaning toA. mixture.B. foundation.C. derivative.D. simulation.（分数：1.00）A.B.C.D.(6).According to Paragraph 4, what can be inferred about “sweet“ natural gas?A. It is more valuable than pure methane gas.B. It contains more sulfur than “sour“ natural gas.C. It has high concentratio
17、ns of propane and butane.D. It requires less refining than “sour“ natural gas.（分数：1.00）A.B.C.D.(7).Why does the author discuss carbon dioxides relationship to global warming in Paragraph 5?A. To illustrate methanes molecular structure.B. To show the link between global warming and smog.C. To suggest
18、 that fossil fuels should not be burned.D. To elaborate on a benefit of natural gass cleanliness.（分数：1.00）A.B.C.D.(8).The word this in the passage refers toA. oil and coal both have complex molecular structures.B. all fossil fuels produce carbon dioxide when burned.C. natural gas releases substantia
19、lly less carbon dioxide than other fuels.D. natural gas emits far less nitrogen and sulfur.（分数：1.00）A.B.C.D.(9).The word emits in the passage is closest in meaning toA. displays.B. gives off.C. affects.D. breaks down.（分数：1.00）A.B.C.D.(10).According to Paragraph 7, one danger of using natural gas is
20、thatA. there is no way to monitor its transfer across oceans.B. its accidental release is hard to notice.C. it is hazardous when mixed with coal or oil.D. large amounts of it must be stored in a single container.（分数：1.00）A.B.C.D.(11).Which of the following statements most accurately reflects the aut
21、hors opinion about natural gas?A. It represents a preferable alternative to other fossil fuel resources.B. Its use in the production of energy carries high costs.C. Its drawbacks will be overcome by technology in the future.D. It should completely replace oil and coal as the worlds energy source.（分数
22、：1.00）A.B.C.D.(12).Look at the four squares that indicate where the following sentence could be added to the passage.Not only does this ensure its protection from severe weather events and other unpredictable hazards, but it also reduces the amount of energy required to move it from place to place.W
23、here would the sentence best fit?Click on a square to add the sentence to the passage.A. Square .B. Square .C. Square .D. Square .（分数：1.00）A.B.C.D.(13).Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choice
24、s that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.Originally, natural gas was not considered a useful commodity and it
25、 has only become a major source of energy in the last century._Answer ChoicesA. Natural gas differs from other fossil fuels in that it is not found in underground deposits.B. Natural gas is extracted from both associated and non-associated sources, and there are many different varieties.C. Some depo
26、sits of natural gas contain high concentrations of impurities such as sulfur and cannot be used commercially.D. Because it burns cleaner than coal and oil, natural gas is much less damaging for the environment.E. One of the main drawbacks in the use of natural gas is that it cannot be piped across o
27、ceans.F. Natural gas is an appealing alternative to other fossil fuels because it is cheaper, more easily transported, and more abundant.（分数：1.00）填空项 1:_三、Set 2(总题数：2，分数：17.00)TOEFL Reading Passage 1The Snakes Forked Tongue1. One of the most intriguing physical characteristics of snakes is their for
28、ked tongues. While this trait is also shared by some types of lizards, all snake species exhibit split tongues, which usually have a more pronounced fork than those of lizards. Any observer of snakes has no doubt noticed that they often stick their tongues out of their mouths, flick them up and down
29、 in the air, and then retract them. In fact, due to a slight indentation in the upper jaw, many species can protrude their tongues without even opening their mouths.2. The explanation for this behavior remained unknown for centuries, giving rise to many folk superstitions. For example, the forked to
30、ngue has become synonymous with deceit, from the idea that two separate tongues would enable a creature to voice two contrasting ideas at the same time. Another popular misconception is that snakes sting other animals with their tongues. Recently, though, scientists uncovered the truth about the for
31、ked tongue, and its actual use is much less sinister.3. Snakes differ greatly from humans on a sensory level. On the one hand, their eyesight is poor and they lack outer ears so they cannot hear with much volume or clarity, but, on the other, some have the ability to “see“ and hunt in the dark by se
32、nsing the body heat of their prey. In addition, snakes have a method of smelling that is peculiar in that it is actually performed by the tongue rather than by the nostrils and nasal cavities, which in fact undertake other functions, such as breathing. When a snake flicks its tongue around in the ai
33、r, it is actually snaring chemical particles, which can be thought of as odors. Next, the snake brings its tongue back in and places it against the roof of its mouth, where there are two small openings that correspond to the two tips of the forked tongue. These make up the snakes Jacobsons organ, a
34、kind of chemoreceptor that analyzes the chemical odors on the tongue and sends this information to the snakes brain.4. This technique for “smelling“ the surrounding environment is truly unique, but even more amazing is the reason why the snakes tongue is forked. By spreading the tips apart when the
35、tongue is flicked out, each samples chemical particles from a slightly different position in the air and brings them back to the Jacobsons organ.The organ then determines which tip was exposed to a larger amount of the particles in question, and this data tells the snake where the source of the odor
36、 can be found. In other words, if the tongues right tip contains more of the particles, such as those of an animals chemical odor, the snake knows that to find the animal it must travel to the right, not to the left.5. Obviously, the ability of snakes to pursue scents in this fashion is very useful
37、in hunting, It has been proven to be quite accurate, allowing them to pick up the trail of rodents and other prey even though the animal itself may be a great distance away. Similarly, if the odor the snake perceives belongs to a predator, it is able to adjust its course to steer clear of the danger
38、, Another suggested use of snakes sense of smell is that it aids them in ascertaining the locations of communal dens*, where snakes reside in groups during the winter months. （分数：8.45）(1).The word pronounced in the passage is closest in meaning toA. controlled.B. obvious.C. evolved.D. useful.（分数：0.6
39、5）A.B.C.D.(2).According to Paragraph 1, many snake species have the ability toA. stick out their tongues while their mouths are shut.B. imitate the behavior of lizards.C. bring prey into their mouths with their tongues.D. retract the lips from their jaws.（分数：0.65）A.B.C.D.(3).In Paragraph 2, why does
40、 the author list folk superstitions?A. To suggest that they inhibited true knowledge about snakes from progressing.B. To emphasize that snakes are considered dangerous by most people.C. To explain the origins of scientific research into snakes tongues.D. To describe the mystery that has been associa
41、ted with snakes irregular tongues.（分数：0.65）A.B.C.D.(4).According to Paragraph 3, how do the senses of snakes differ from those of humans?A. Snakes use their nostrils and nasal cavities when smelling.B. Snakes have less developed hearing abilities than humans.C. Snakes eyesight is better at night tha
42、n during the day.D. Snakes sensitivity to heat is less than that of humans.（分数：0.65）A.B.C.D.(5).5, The word snaring in the passage is closest in meaning toA. testing.B. keeping.C. forming.D. catching.（分数：0.65）A.B.C.D.(6).The word These in the passage refers toA. particles.B. openings.C. tips.D. odor
43、s.（分数：0.65）A.B.C.D.(7).Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.A. Snakes have an unusual method of smelling which is similar to the way
44、other animals breathe.B. As well as being used for smelling, the nostrils and nasal cavities also serve the additional function of allowing the snake to breathe.C. Uniquely, a snakes tongue is what helps it to pick up scents, and its nostril or nasal cavity is for other tasks.D. As well as having pe
45、culiar tongues, snakes also have distinctive nostrils and nasal cavities.（分数：0.65）A.B.C.D.(8).According to Paragraph 4, what is the function of the Jacobsons organ in snakes?A. To assist in the search for chemical particles in the air.B. To enable the tongues fork to be spread more widely.C. To util
46、ize the snakes trained sense of direction.D. To compare the sensory input of the two tongue tips.（分数：0.65）A.B.C.D.(9).The word perceives in the passage is closest in meaning toA. imitates.B. discharges.C. notices.D. carries.（分数：0.65）A.B.C.D.(10).All of the following are mentioned in Paragraph 5 and
47、Paragraph 6 as ways in which snakes use their tongues EXCEPTA. avoiding animals that may pose a threat to them.B. finding a snake of the opposite sex in order to reproduce.C. following other snakes during cooperative hunts.D. determining the location of potential food sources.（分数：0.65）A.B.C.D.(11).W
48、hat can be inferred from Paragraph 6 about the pheromones of female snakes?A. They are produced year round.B. They are species specific.C. They are only detectable by male snakes.D. They are the strongest chemical odors.（分数：0.65）A.B.C.D.(12).Look at the four squares that indicate where the following
49、 sentence could be added to the passage.Young snakes especially may rely on their tongues and Jacobsons organs to follow the scents left by adults on their way to these hibernation spots.Where would the sentence best fit?Click on a square to add the sentence to the passage.A. Square .B. Square .C. Square .D. Square .（分数：0.65）A.B.C.D.(13).Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most im
