TOEFL Writing Correction Topics

QUESTION: Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.

Reading passage

The Salton Sea in California is actually a salty inland lake. The level of salt in the lake's water - what scientists call its salinity - has been increasing steadily for years because the lake’s water is evaporating faster than it is being replaced by rainfall or rivers. If the trend continues, the lake's water will soon become so salty that the lake will be unable to support fish and bird populations. The lake would then become essentially a dead zone. Fortunately, there are several ways to reverse the trend that is threatening the lakes health.

One option is direct removal of salt from the lake’s water in special desalination facilities. Water from the lake would be pumped into the facilities and heated. This would cause the water to evaporate into steam, while salt and other materials dissolved in the water would be left behind. The steam would then be cooled down and returned to the lake as salt-free water. Gradually, the high salt levels would be reduced and the lake's overall health would be restored.

Another possible solution is to dilute the salt level in the lake with water from the ocean. Since water in the Pacific Ocean is 20 percent less salty than water in the lake, bringing ocean water into the lake would decrease the lake’s salinity. The ocean water could be delivered through pipelines or canals.

Yet another solution would be to control the lake's salinity by constructing walls to divide the lake into several sections. In the smaller sections, salinity would be allowed to increase. However, in the main and largest section, salinity would be reduced and controlled by, among other things, directing all the freshwater from small rivers in the area to flow into that main section of the lake.

QUESTION: Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.

Reading passage

In the United States, it had been common practice since the late 1960s not to suppress natural forest fires. The “let it burn” policy assumed that forest fires would burn themselves out quickly, without causing much damage. However, in the summer of 1988, forest fires in Yellowstone, the most famous national park in the country, burned for more than two months and spread over a huge area, encompassing more than 800,000 acres. Because of the large scale of the damage, many people called for replacing the “let it burn” policy with a policy of extinguishing forest fires as soon as they appeared. Three kinds of damage caused by the “let it burn” policy were emphasized by critics of the policy.

First, Yellowstone fires caused tremendous damage to the park’s trees and other vegetation. When the fires finally died out, nearly one third of Yellowstone’s land had been scorched. Trees were charred and blackened from flames and smoke. Smaller plants were entirely incinerated. What had been a national treasure now seemed like a devastated wasteland.

Second, the park wildlife was affected as well. Large animals like deer and elk were seen fleeing the fire. Many smaller species were probably unable to escape. There was also concern that the destruction of habitats and the disruption of food chains would make it impossible for the animals that survived the fire to return.

Third, the fires compromised the value of the park as a tourist attraction, which in turn had negative consequences for the local economy. With several thousand acres of the park engulfed in flames, the tourist season was cut short, and a large number of visitors decided to stay away. Of course, local businesses that depended on park visitors suffered as a result.

QUESTION: Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.

Reading passage

As early as the twelfth century A.D., the settlements of Chaco Canyon in New Mexico in the American Southwest were notable for their "great houses" - massive stone buildings that contain hundreds of rooms and often stand three or four stories high. Archaeologists have been trying to determine how the buildings were used. While there is still no universally agreed upon explanation, there are three competing theories.

One theory holds that the Chaco structures were purely residential, with each housing hundreds of people. Supporters of this theory have interpreted Chaco great houses as earlier versions of the architecture seen in more recent Southwest societies. In particular, the Chaco houses appear strikingly similar to the large, well-known "apartment buildings" at Taos, New Mexico, in which many people have been living for centuries.

A second theory contends that the Chaco structures were used to store food supplies. One of the main crops of the Chaco people was grain maize, which could be stored for long periods of time without spoiling and could serve as a long-lasting supply of food. The supplies of maize had to be stored somewhere, and the size of the great houses would make them very suitable for the purpose.

A third theory proposes that houses were used as ceremonial centers. Close to one house, called Pueblo Alto, archaeologists identified an enormous mound formed by a pile of old material. Excavations of the mound revealed deposits containing a surprisingly large number of broken pots. This finding has been interpreted as evidence that people gathered at Pueblo Alto for special ceremonies. At the ceremonies, they ate festive meals and then discarded the pots in which the meals had been prepared or served. Such ceremonies have been documented for other Native American cultures.

QUESTION: Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.

Reading passage

Ethanol fuel, made from plants such as corn and sugar cane, has been advocated by some people as an alternative to gasoline in the United States. However, many critics argue that ethanol is not a good replacement for gasoline for several reasons.

First, the increased use of ethanol fuel would not help to solve one of the biggest environmental problems caused by gasoline use: global warming. Like gasoline, ethanol releases carbon dioxide into the atmosphere when it is burned for fuel and carbon dioxide is greenhouse gas: it helps trap heat in the atmosphere. Thus, ethanol offers no environmental advantage over gasoline.

Second, the production of significant amounts of ethanol would dramatically reduce the amount of plants available for uses other than fuel. For example, much of the corn now grown in the United States is used to feed farm animals such as cows and chickens. It is estimated that if ethanol were used to satisfy just 10 percent of the fuel needs in the United States, more than 60 percent of the corn currently grown in the United States would have to be used to produce ethanol. If most of the corn were used to produce ethanol, a substantial source of food for animals would disappear.

Third, ethanol fuel will never be able to compete with gasoline on price. Although the prices of ethanol and gasoline for the consumer are currently about the same, this is only because of the help in the form of tax subsidies given to ethanol producers by the United States government. These tax subsidies have cost the United States government over $11 billion in the past 30 years. If the United States government were to stop helping producers in this way, the price of ethanol would increase greatly.

QUESTION: Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.

Reading passage

Humans have long been fascinated by elephants, the largest land animal in the modern world. Social animals that live in herds, elephants are native to both Africa and Asia. Their large ears, long trunk, and long life span have made elephants one of the most captivating creatures on Earth. Our long-standing interest in elephants has led to several beliefs about surprising elephant behaviors.

Elephants Are Aware of Approaching Death
One of the popular beliefs is that when elephants become old and weak, they know that they are nearing the end of their lives. They demonstrate this by breaking away from their herds and going off alone to certain locations often found near bodies of water - so called "elephant graveyards" - to die alone. The idea that old elephants seem aware that they will die soon is supported by the discovery of many sites containing bones exclusively of elderly elephants.

Representing Objects through Art
Additionally, elephants seem to have artistic ability. Elephants can be taught to hold a paintbrush in their trunk and use it to paint on a canvas. Some elephants have been known to paint drawings that represent recognizable things: flowers, other elephants, even themselves. This talent makes elephants the only animal other than humans to produce art representing the world around them.

Fear of Mice
Finally, it has long been believed that elephants have a fear of mice. In 77 C.E., the Roman philosopher and scientist Pliny the Elder wrote that elephants are more afraid of mice - small mammals that can do elephants no harm - than of the much more dangerous animals with which elephants normally share an environment, such as lions or tigers. In a recent scientific experiment in which a herd of elephants was confronted with several mice, the elephants backed away from the mice and left the area to avoid them.

QUESTION: Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.

Reading passage

Pterosaurs were an ancient group of winged reptiles that lived alongside the dinosaurs. Many pterosaurs were very large, some as large as a giraffe and with a wingspan of over 12 meters. Paleontologists have long wondered whether large pterosaurs were capable of powered flight (flying by flapping their wings) or whether they were able only to glide. Several arguments have been made against powered flight.

Doubters point out that since modern reptiles are cold-blooded, ancient reptiles such as pterosaurs were probably cold-blooded as well. Cold-blooded animals typically have a slow metabolism and are unable to produce a lot of energy. Powered flight is an activity requiring a lot of energy, which is why all modern vertebrates that fly are warm-blooded, not cold-blooded. It seemed unlikely that pterosaurs would have been able to generate the energy needed to fly.

Second, there is a limit to the weight of animals that can be kept airborne by powered flight. Pterosaurs that were as large as a giraffe were probably so heavy that they would not have been able to flap their wings fast enough to stay aloft for any length of time.

Third, all animals with powered flight are able to take off from the ground. For example, birds take off by jumping from their legs or running to gain speed and then jumping. But these methods would not have worked for large pterosaurs. Large pterosaurs would have needed big, powerful muscles in their back legs to launch themselves into the air, and we know from fossilized bones that their back leg muscles were too small and weak to allow the pterosaurs to run fast enough or jump high enough to launch themselves into the air.

QUESTION: Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.

Reading passage

Scientists are considering the possibility of sending humans to Mars in the coming decades. Although there have been successful manned missions to the Moon in the 1960s and 1970s, Mars is 150 times further away from Earth than the Moon is. Thus the project of sending humans to Mars would require solving an array of problems the Moon missions did not have to face.

One problem is that a round-trip to Mars and back is likely to take at least two years. The trip to the Moon lasted only a few days, and it was easy to bring enough supplies of food, water, and oxygen; but the cargo capacity of space vehicles is too limited to put on board the food, water, and oxygen required by a crew for a period of two years. Without those essentials, though, a Mars mission is impossible.

A second problem is that astronauts on the Mars mission would be in the zero-gravity environment of space for many months at a time. Spending a long time in the zero-gravity environment has negative effects on the human body, such as decreased muscle mass and lower bone density. Over the course of a two-year mission, the effects would be so severe, they would make it impossible for humans to make the trip without experiencing grave medical problems.

Finally, astronauts on a mission to Mars would be exposed to dangerous levels of space radiation, much of which comes in the form of charged particles emitted by the Sun. Earth's magnetic field, which normally protects us from dangerous solar radiation, would not be able to protect a spaceship traveling in interplanetary space. Constructing a shield that would protect the whole spaceship from space radiation is at present impossible because it would add too much weight to the ship.

QUESTION: Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.

Reading passage

Hail - pieces of ice that form and fall from clouds instead of snow or rain—has always been a problem for farmers in some areas of the United States. Hail pellets can fall with great force and destroy crops in the field. Over the last few decades, a method of reducing hail, called "cloud seeding," has been tried. In cloud seeding, the chemical silver iodide is sprayed on storm clouds from an airplane. This makes the clouds produce harmless rain or snow instead of hail. Several pieces of evidence suggest that cloud seeding has been effective in protecting crops from hail.

Laboratory experiments
Experiments in the laboratory support the idea that cloud seeding is effective. Hail usually forms water vapor that is close to the freezing point. However, when experimenters added silver iodide to cold water vapor in the laboratory, they often observed light snow forming instead of hail pellets.

Evidence from Asia
There is evidence about the effectiveness of cloud seeding from several countries around the world. In some Asian countries, for example, cloud seeding has been successfully used to control precipitation in urban areas. These positive results suggest that cloud seeding should also be effective in protecting fields and farms in the United States.

Local studies
A few local studies also support the value of cloud seeding. One study conducted in a farming region in the central United States, for example, directly monitored crop damage due to hail. The study found that in an area where cloud seeding was used there was reduced hail damage compared to previous years.

QUESTION: Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.

Reading passage

Many consumers ignore commercial advertisements. In response, advertising companies have started using a new tactic, called “buzzing.” The advertisers hire people—buzzers—who personally promote (buzz) products to people they know or meet. The key part is that the buzzers do not reveal that they are being paid to promote anything. They behave as though they were just spontaneously praising a product during normal conversation. Buzzing has generated a lot of controversy, and many critics would like to see it banned.

First, the critics complain that consumers should know whether a person praising a product is being paid to praise the product. Knowing this makes a big difference: we expect the truth from people who we believe do not have any motive for misleading us. But with buzzing what you hear is just paid advertising, which may well give a person incorrect information about the buzzed product.

Second, since buzzers pretend they are just private individuals, consumers listen to their endorsements less critically than they should. With advertisements in print or on TV, the consumer is on guard for questionable claims or empty descriptions such as “new and improved.” But when consumers do not know they are being lobbied, they may accept claims they would otherwise be suspicious of. This may suit the manufacturers, but it could really harm consumers

And worst of all is the harmful effect that buzzing is likely to have on social relationships. Once we become aware that people we meet socially may be buzzers with a hidden agenda, we will become less trustful of people in general. So buzzing will result in the spread of mistrust and the expectation of dishonesty.

QUESTION: Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.

Reading passage

Jane Austen (1775-1817) is one of the most famous of all English novelists, and today her novels are more popular than ever, with several recently adapted as Hollywood movies. But we do not have many records of what she looked like. For a long time, the only accepted image of Austen was an amateur sketch of an adult Austen made by her sister Cassandra. However, recently a professionally painted, full-length portrait of a teenage girl owned by a member of the Austen family has come up for sale. Although the professional painting is not titled Jane Austen, there are good reasons to believe she is the subject.

First, in 1882, several decades after Austen's death, Austen's family gave permission to use the portrait as an illustration in an edition of her letters. Austen's family clearly recognized it as a portrait of the author. So, for over a century now, the Austen family itself has endorsed the claim that the girl in the portrait is Jane Austen.

Second, the face in the portrait clearly resembles the one in Cassandra's sketch, which we know depicts Austen. Though somewhat amateurish, the sketch communicates definite details about Austen's face. Even though the Cassandra sketch is of an adult Jane Austen, the features are still similar to those of the teenage girl in the painting. The eyebrows, nose, mouth, and overall shape of the face are very much like those in the full-length portrait.

Third, although the painting is unsigned and undated, there is evidence that it was painted when Austen was a teenager. The style links it to Ozias Humphrey, a society portrait painter who was the kind of professional the wealthy Austen family would hire. Humphrey was active in the late 1780s and early 1790s, exactly the period when Jane Austen was the age of the girl in the painting.