【听力】

    综述：该次考试只有一个section机经，对话是服务咨询，而大学餐厅一直是高频考点，关于meal plan也常常会考点，大家要留意。讲座考试的社会科学里高频的历史学，一听你必定会听到很多时间，时间本身不是关键考点，但通过时间能帮助我们理清历史题材段子的结构，非常好用。另外一篇是艺术，今年大陆托福听力考试中艺术学科有多次考艺术家，本次北美考试又考到了。大家可以把TPO中几篇考艺术家的文章放在一起做题和总结文章结构，这样必有收获。

Section 1:

　　Conversation 1：【对话-服务咨询-食堂】

　　要点：

　　有个Cafeteria Manager跟女学生的对话;

　　女学生要搬出去，不住dorm，想把Meal Plan 取消。但是Manager说一旦买了就不可以取消;

　　然后讲了一大堆他们Cafeteria的食物有多好，有新菜等等;

　　后来女学生问他有没有别的办法，他说能咨询一下是否能把Meal Plan转到其他Building的Cafe.

　　Lecture 1：【讲座-社会科学-历史】

　　世界历史，讲tea trade between Asia & Europe;

　　tea 在什么时候到哪里的，一开始先到荷兰;再到英国，在英国广泛流传;

　　一开始只有达官贵族能喝到tea,后来tea又用来当药用;之后有个princess(忘记名字了，会有提示)教群众如何将tea变得没那么苦。后来又发明将糖加到tea里面会很好喝;

　　也说了coffee没有广泛被需要的原因，是生产shortage，问的是culture trend的相关问题。

　　Lecture 2：【讲座-艺术-艺术家】

　　Art, 近代美国艺术家child Hassam

　　作品the breakfast room, winter morning, 1911，说他的作品受环境的影响。

Section 2 【暂缺】

【阅读】

篇:

　　地质学，讲的是大气如何形成

　　(注：此篇可结合TPO16的第三篇Planets in our solar system中与大气相关内容阅读)

　　Atmosphere

　　Atmosphere, mixture of gases surrounding any celestial object that has a gravitational field strong enough to prevent the gases from escaping; especially the gaseous envelope of Earth. The principal constituents of the atmosphere of Earth are nitrogen (78 percent) and oxygen (21 percent). The atmospheric gases in the remaining 1 percent are argon (0.9 percent), carbon dioxide (0.03 percent), varying amounts of water vapor, and trace amounts of hydrogen, ozone, methane, carbon monoxide, helium, neon, krypton, and xenon.

　　The mixture of gases in the air today has had 4.5 billion years in which to evolve. The earliest atmosphere must have consisted of volcanic emanations alone. Gases that erupt from volcanoes today, however, are mostly a mixture of water vapor, carbon dioxide, sulfur dioxide, and nitrogen, with almost no oxygen. If this is the same mixture that existed in the early atmosphere, then various processes would have had to operate to produce the mixture we have today. One of these processes was condensation. As it cooled, much of the volcanic water vapor condensed to fill the earliest oceans. Chemical reactions would also have occurred. Some carbon dioxide would have reacted with the rocks of Earth’s crust to form carbonate minerals, and some would have become dissolved in the new oceans. Later, as primitive life capable of photosynthesis evolved in the oceans, new marine organisms began producing oxygen. Almost all the free oxygen in the air today is believed to have formed by photosynthetic combination of carbon dioxide with water. About 570 million years ago, the oxygen content of the atmosphere and oceans became high enough to permit marine life capable of respiration. Later, some 400 million years ago, the atmosphere contained enough oxygen for the evolution of air-breathing land animals.

　　The water-vapor content of the air varies considerably, depending on the temperature and relative humidity. With 100 percent relative humidity, the water-vapor content of air varies from 190 parts per million (ppm) at -40°C (-40°F) to 42,000 ppm at 30°C (86°F). Minute quantities of other gases, such as ammonia, hydrogen sulfide, and oxides of sulfur and nitrogen, are temporary constituents of the atmosphere in the vicinity of volcanoes and are washed out of the air by rain or snow. Oxides and other pollutants added to the atmosphere by industrial plants and motor vehicles have become a major concern, however, because of their damaging effects in the form of acid rain. In addition, the strong possibility exists that the steady increase in atmospheric carbon dioxide, mainly as the result of the burning of fossil fuels since the mid-1800s, may affect Earth’s climate (see Greenhouse Effect).

　　Similar concerns are posed by the sharp increase in atmospheric methane. Methane levels have risen 11 percent since 1978. About 80 percent of the gas is produced by decomposition in rice paddies, swamps, and the intestines of grazing animals, and by tropical termites. Human activities that tend to accelerate these processes include raising more livestock and growing more rice. Besides adding to the greenhouse effect, methane reduces the volume of atmospheric hydroxyl ions, thereby curtailing the atmosphere’s ability to cleanse itself of pollutants. See also Air Pollution; Climate; Smog.

　　The study of air samples shows that up to at least 88 km (55 mi) above sea level the composition of the atmosphere is substantially the same as at ground level; the continuous stirring produced by atmospheric currents counteracts the tendency of the heavier gases to settle below the lighter ones. In the lower atmosphere, ozone, a form of oxygen with three atoms in each molecule, is normally present in extremely low concentrations. The layer of atmosphere from 19 to 48 km (12 to 30 mi) up contains more ozone, produced by the action of ultraviolet radiation from the sun. Even in this layer, however, the percentage of ozone is only 0.001 by volume. Atmospheric disturbances and downdrafts carry varying amounts of this ozone to the surface of Earth. Human activity adds to ozone in the lower atmosphere, where it becomes a pollutant that can cause extensive crop damage.

　　The ozone layer became a subject of concern in the early 1970s, when it was found that chemicals known as chlorofluorocarbons (CFCs), or chlorofluoromethanes, were rising into the atmosphere in large quantities because of their use as refrigerants and as propellants in aerosol dispensers. The concern centered on the possibility that these compounds, through the action of sunlight, could chemically attack and destroy stratospheric ozone, which protects Earth’s surface from excessive ultraviolet radiation. As a result, industries in the United States, Europe, and Japan replaced chlorofluorocarbons in all but essential uses. See Aerosol Dispenser; Ozone Layer; Photochemistry.

　　The atmosphere may be divided into several layers. In the lowest one, the troposphere, the temperature as a rule decreases upward at the rate of 5.5°C per 1,000 m (3°F per 3,000 ft). This is the layer in which most clouds occur (see Cloud). The troposphere extends up to about 16 km (about 10 mi) in tropical regions (to a temperature of about -79°C, or about -110°F) and to about 9.7 km (about 6 mi) in temperate latitudes (to a temperature of about -51°C, or about -60°F). Above the troposphere is the stratosphere. In the lower stratosphere the temperature is practically constant or increases slightly with altitude, especially over tropical regions. Within the ozone layer the temperature rises more rapidly, and the temperature at the upper boundary of the stratosphere, almost 50 km (about 30 mi) above sea level, is about the same as the temperature at the surface of Earth. The layer from 50 to 90 km (30 to 55 mi), called the mesosphere, is characterized by a marked decrease in temperature as the altitude increases.

　　From investigations of the propagation and reflection of radio waves, it is known that beginning at an altitude of 60 km (40 mi), ultraviolet radiation, X rays (see X Ray), and showers of electrons from the sun ionize several layers of the atmosphere, causing them to conduct electricity; these layers reflect radio waves of certain frequencies back to Earth. Because of the relatively high concentration of ions in the air above 60 km (40 mi), this layer, extending to an altitude of about 1000 km (600 mi), is called the ionosphere. At an altitude of about 90 km (55 mi), temperatures begin to rise. The layer that begins at this altitude is called the thermosphere, because of the high temperatures reached in this layer (about 1200°C, or about 2200°F). The region beyond the thermosphere is called the exosphere, which extends to about 9,600 km (about 6,000 mi), the outer limit of the atmosphere.

　　The density of dry air at sea level is about 1/800 the density of water; at higher altitudes it decreases rapidly, being proportional to the pressure and inversely proportional to the temperature. Pressure is measured by a barometer and is expressed in millibars, which are related to the height of a column of mercury that the air pressure will support; 1 millibar equals 0.75 mm (0.03 in) of mercury. Normal atmospheric pressure at sea level is 1,013 millibars, that is, 760 mm (29.92 in) of mercury. At an altitude of 5.6 km (about 3.5 mi) pressure falls to about 507 millibars (about 380 mm/14.96 in of mercury); half of all the air in the atmosphere lies below this level. The pressure is approximately halved for each additional increase of 5.6 km in altitude. At 80 km (50 mi) the pressure is 0.009 millibars (0.0069 mm/0.00027 in of mercury).

　　第二篇：

　　生物学，果蝇和青蛙成长的不同时期需要什么

　　第三篇：

　　bird nesting,说鸟喜欢在colonies筑巢，说了有什么好处，有一种鸟有自我保护意思，可以群体攻击那些天敌，有些seabird都在哪里筑巢比较安全，同时，集体筑巢又有什么隐患，例如吸引大量天敌。etc.

　　Bird Nesting Colonies

　　In many species, including herons, swallows, and most seabirds, individual birds come together each year to build nests near the nests of many others of the species. The resulting aggregations are called nesting colonies. Colonial nesting involves a number of factors. Seabirds, for example, often forage widely over the ocean surface, where the only available nesting land may be an island of limited area. The birds may also prefer an island to mainland nesting sites because it is safer, being inaccessible to most land predators. Also, by watching their neighbors returning to the colony with food for their chicks, colony-nesting gulls, or puffins may learn from one another where they can forage most successfully. Bank and Cliff Swallows, for example, build their nests in sites protected from ground predators such as foxes, skunks, and weasels.

　　Because residents in a colony usually share their feeding sites, colonial nesters are not, strictly speaking, territorial birds. They do, however, defend their nests against the adjacent birds, and with good reason: Colony members are known to sometimes steal nesting material from one another. They have also been known to sneak eggs into other birds' nests and to seduce other birds' mates. On the positive side, a few colony nesters have been known, on rare occasions, to feed another neighbor's chicks.

　　Bird Colonies

　　The habit of nesting in groups is believed to provide better survival against predators in several ways. Many colonies are situated in locations that are naturally free of predators. In other cases, the presence of many birds means there are more individuals available for defense. Also, synchronized breeding leads to such an abundance of offspring as to satiate predators.

　　For seabirds, colonies on islands have an obvious advantage over mainland colonies when it comes to protection from terrestrial predators. Other situations can also be found where bird colonies avoid predation. A study of Yellow-rumped Caciques in Peru found that the birds, which build enclosed, pouch-like nests in colonies of up to one hundred active nests, situate themselves near wasp nests, which provide some protection from tree-dwelling predators such as monkeys. When other birds came to rob the nests, the caciques would cooperatively defend the colony by mobbing the invader. Mobbing, clearly a group effort, is well-known behavior, not limited to colonial species; the more birds participating in the mobbing, the more effective it is at driving off the predator. Therefore, it has been theorized that the larger number of individuals available for vigilance and defense makes the colony a safer place for the individual birds nesting there. More pairs of eyes and ears are available to raise the alarm and rise to the occasion.

　　Another suggestion is that colonies act as information centers and birds that have not found good foraging sites are able to follow others, who have fared better, to find food. This makes sense for foragers because the food source is one that can be locally abundant. This hypothesis would explain why the Lesser Kestrel, which feeds on insects, breeds in colonies, while the related Common Kestrel, which feeds on larger prey, is not.

　　Colonial behaviour has its costs as well. It has been noted that parasitism by haematozoa is higher in colonial birds and it has been suggested that blood parasites might have shaped adaptations such as larger organs in the immune system and life-history traits. Other costs include brood parasitism and competition for food and territory. Colony size is a factor in the ecological function of colony nesting. In a larger colony, increased competition for food can make it harder for parents to feed their chicks.

　　The benefits and drawbacks for birds of nesting in groups seem to be highly situational. Although scientists have hypothesized about the advantages of group nesting in terms of enabling group defensive behavior, escape from predation by being surrounded by neighbors (called the selfish herd hypothesis), as well as escaping predators through sheer numbers, in reality, each of these functions evidently depends on a number of factors. Clearly, there can be safety in numbers, but there is some doubt about whether it balances out against the tendency for conspicuous breeding colonies to attract predators, and some suggest that colonial breeding can actually make birds more vulnerable. At a Common Tern colony in Minnesota, a study of Spotted Sandpipers observed to nest near the tern colony showed that the sandpipers that nested nearest the colony seemed to gain some protection from mammalian predators, but avian predators were apparently attracted to the colony and the sandpipers nesting there were actually more vulnerable. In a study of a Least Tern colony in Connecticut, nocturnal avian predators in the form of Black-crowned Night Herons and Great Horned Owls were observed to repeatedly invade a colony, flying into the middle of the colony and meeting no resistance.

　　For seabirds, the location of colonies on islands, which are inaccessible to terrestrial predators, is an obvious advantage. Islands where terrestrial predators have arrived in the form of rats, cats, foxes, etc., have devastated island seabird colonies. One well-studied case of this phenomenon has been the effect on Common Murre colonies on islands in Alaska, where foxes were introduced for fur farming.

【写作】

综合写作：

　　dental amalgam

　　Reading提到三点，对人，环境的不好，以及其他替补的可能性;

　　lecture也提到三点，对人， 对环境 如何保护，以及其他material性价比不够amalgam好;

　　独立写作：

　　Do you agree or disagree with the following statement? Though modern agricultural practices damage the environment, feeding the world's growing population is more important than protecting against environmental damage.

　　It is often said that the world population grows following a geometric progression (2, 4, 8, 16, 32...) but food production grows following an arithmetic production (1, 2, 3, 4, 5...). If this were true, then one would expect the world's food demands to quickly outpace its ability to meet those demands. This does appear to be the case, at least on the surface—more than half of the world population perishes each year from malnutrition. But is this a food production problem, and should food production thus be pursued with reckless disregard for the environment? I do not believe so.

　　The problem of world hunger is not a problem of food production, but rather, one of food distribution and poverty. In many of the developing countries where scores die every year of malnutrition, there are actually sizable surpluses of food; the real issue is that those who need it the most cannot afford to buy it, and so the supplies are sold to more wealthy nations that cannot meet their own agricultural needs through domestic production. For many decades now, there has been enough food in the world to feed the entire world population—it is just a matter of getting it into the right hands.

　　Thus, engaging in harmful agricultural practices for the sake of higher food production would actually be counter-productive in the long run. First of all, it would do nothing to solve the current socio-economic and political inequality that leads to such huge disparities in food allocation. Second of all, it would probably harm those that we were trying to help. This is because most of the harmful practices would likely be implemented in disadvantaged countries, seeing as wealthy countries would have little room left for further agricultural growth. Unsustainable agricultural land development, aggressive use of fertilizers—these measures, while perhaps supplying food in the short term, would ultimately deplete the natural environment and handicap a country's growth in the future, landing them back where they started.

　　Granted, the long view will provide little consolation to those who are desperately in need of food now. Some argue that it is better to make environmental sacrifices in order to start saving lives today, and to just deal with serious environmental problems down the line as they arise. While I believe there is some merit to this, I do not think that should be the first option we turn to—wouldn't it make much more sense to just tackle the poverty and distribution problem directly, alleviating hunger through more considered means, and avoid the potential environmental pitfalls entirely?

　　The situation presents difficult ethical quandary—do we choose to let people suffer now, so that more may avoid pain later? Or do we help them now, and hope that we do not dig everybody into an even bigger hole down the line? Ultimately it will be a trying decision, but what is clear is that something must be done; though neither choice is without its drawbacks, they are both preferable to inaction.

　　以上就是3月22日北美托福写作机经整理，希望各位考友合理利用机经，认真备考，获得一个自己理想的成绩。

【口语】

    Task 1: Which of the following Art classes would you be more interested in taking? Wood Sculpture, Painting or Photography?

　　三选一，可以学一样art，选哪样? wood sculpture; painting; 摄影;

　　参考答案

　　I prefer to take Photography course out of the three for the following reasons. First of all, taking photos is fun! Photography gives us a chance to see the world around us differently. It trains our eyes to spot things that are interesting out of the ordinary. Second, Every second that you live is a second more in the past. Every picture that is taken captures those split seconds and stores them timelessly. Pictures are a chart of memories and moments that can be revisited as they were when the image is viewed.

　　4/6. sociology，一个女教授说不同种群的人会用自己创造的语音来进行对话。举了两个例子;一个是医生们用自己有的专业知识来进行交流，但对病人就要详细说明;一个是一群share experience的人，有过共同经历，只要mention 事情的keyword就能引起共鸣。 summarize一下就可以了。

　　解析：

　　Key Points:

　　Main idea: The professor tells us that different people use different ways to communicate with each other.

　　Way 1: Doctors use terminology to communicate with each other but they have to be more specific when they communicate with their patients.

　　Way 2: In a group that shares experiences, they only have to mention the keywords of something to communicate.

　　5. 情景对话，女孩组织一个spring concert 明晚就举行了，但是天气报告说有可能下雨。她有两个solution:改地点到 auditorium;但是本来个音乐会在室外举行，应该会很热闹。她有她的concern' 或者改时间到 the day after tomorrow; 她又担心周日人会不够多，concert不够热闹。然后你二选一，explain一下如何帮她做这个抉择

　　解析：

　　Key Points:

　　Problem:

　　The girl is going to hold a spring concert tomorrow evening, but the forecast says that it might rain tomorrow.

　　Solution 1： Change the location to the auditorium

　　Comment: But it will be more popular and livelier if the concert is held outside.

　　Solution 2: She can change the time to the day after tomorrow.

　　Comment: But she is worried that there won’t be too many people coming around on Sunday.