2025年7月29日上午场托福写作完整版答案及解析（含范文）

阅读

听力

　主题：cactus如何到达非洲

　　Birds

　　The first theory is that the wicker cactus was spread like many other plants: by birds. Its seeds could have been eaten by a migrating bird, which stored them in its digestive tract and then passed them on as waste after crossing to another continent. In a suitable environment on the new continent, the plants could have developed from these transported seeds and then reproduced. This theory is supported by the fact that many bird species are known to make regular migrations of great distances.

　　First, about birds spreading seeds. Well, some birds do eat the seeds of the wicker cactus. The cactus produces small white fruits with the seeds inside them. And some species of birds eat the fruit and spread its seeds through their digestion. The problem is that none of these bird species typically fly directly across the Atlantic ocean, from the Americas to Africa. There are other birds that cross the Atlantic ocean and travel from the Americas to Africa regularly. But those birds mainly eat insects and fish, they typically don't feed on fruit. So they probably would not consume wicker cactus seeds.

　　Predates separation of continents

　　A second theory is that the wicker cactus has existed for so long that it is actually older than the ocean that now separates Africa and South America. Long ago, Africa and South America were part of one giant continent. In this explanation, the wicker cactus first evolved during the ancient time before the continents separated. As the two land masses slowly drifted apart over millions of years, early wicker cactus plants were left on each side of the ocean.

　　The idea that the wicker cactus evolved before the continent separated has been called into question. You see, until recently, no one knew exactly when cactus species first evolved. But researchers can now study the DNA or genes of a species to estimate how long this species has existed. And new DNA studies suggest that no cactus existed when south America and Africa were connected in one giant continent. Based on the DNA studies, scientists now believe that all cactus species, including the wicker cactus, first evolved much later. Millions of years after the separation of continents.

　　Sailors

　　The third theory is that sixteenth-century sailors carried the wicker cactus from South America to Africa on their boats. Records show that when Portuguese and Spanish sailors traveled to the Americas, they frequently brought plants back and forth across the ocean. Since the wicker cactus can survive for a long time without soil, it could have easily lived through such a trip.

　　Third, the sailor theory. If sailors had carried the wicker cactus to Africa on boats, we would expect to find it growing, mostly in places where ships would have arrived. Near ports. But the wicker practice usually grows in parts of Africa that are far away from ports and not in any of Africa’s port cities. What's more, some of the places where the cactus is found are very far. Deep in the middle of the African continent. In areas, ships could never even approach.

阅读

听力

　主题：prairie dog 是否应该被保护

　　First, cattle farmers have long argued that prairie dogs should not be protected, because they are agricultural pests. The farmers point out that prairie dogs compete with cattle for grass that cattle graze on. Prairie dogs live in large groups that build networks of burrows underground and feed on the grass above their burrows. The farmers have argued that the loss of grass to prairie dogs creates a real economic problem for them.

　　First, the idea that the prairie dogs are serious tests is outdated. It originated in the early nineteen hundreds, and it makes sense at that time, but nowadays most of the cows raised in the US do not get their food by grazing freely on the grassland but by being fed processed feed in closed feeding areas. Grass is no longer as precious resource for cattle farmers as it once was. Furthermore, some studies indicate that prairie dog activities actually make the soil in the grasslands more fertile. So the presence of prairie dogs is actually beneficial to the growth of the glasses.

　　Second, prairie dogs may represent a serious health hazard, since they often become infected with plague, a dangerous bacterial disease that can infect people as well. Like many rodents, prairie dogs carry fleas, insects that can transmit the plague bacteria from prairie dogs to humans.

　　Second, it's extremely rare for plague to actually spread from prairie dogs to humans. One reason for this is that the type of flea that lives on the bodies of prairie dogs does not tend to live on human bodies. So the transmission of the plague by flees to humans is extremely unlikely. Let me give you some figures to illustrate how rare it is. In the state of Colorado , only ten people were infected with plagues who contacted with the prairie dogs in the last fifteen years.

　　Third, some people argue that prairie dogs do not have enough ecological importance to deserve special protection. According to this argument, it makes much more ecological sense to protect species at the top of the food chain-meat eaters such as wolves or bears-because those animals have a large impact on the balance of the whole ecosystem. Plant eaters like the prairie dogs have a more limited impact, and protecting them would not make much difference to the broader ecosystem.

　　Third, prairie dogs do play an important ecological role even though they are just plant eaters. For example, the underground borrows that prairie dogs create present an important habitat for other species. Animals like salamanders and snakes live in those burrows. Also, prairie dogs are a critical food service for dozens of predators. Foxes, coyotes and some rare species of predators as well. So the continued loss of prairie dogs would have a negative impact on many species in the prairie ecosystems.

阅读

听力

　主题：尼加拉瓜运河和巴拿马运河的优缺点

　　First, a canal through Nicaragua would facilitate faster transport of goods between Asia and the East Coast of the United States. Ships coming from Asia have to travel farther south to reach the Panama Canal than they would to reach a canal in Nicaragua. Building a canal through Nicaragua would cut about 500 nautical miles off the journey between Asia and the East Coast of the United States.

　　It is true that the distance that ships would have to cover on the open seas between Asia and the east coast of the united states would be significantly reduced. But the problem is that ships going through the garigue would have to spend more time passing through the canal itself. That's because the country of Nicaragua is much wider than Panama. In fact, A canal built across Nicaragua would be more than three times longer than the Panama canal. Ships moving through a canal move very slowly. And so any time gained by ships and covering less distance on the open seas would be lost in passing through the near or canal itself.

　　Second, a canal through Nicaragua could allow for the transit of larger ships. As global trade over long distances grows in importance, shipping companies may try to increase efficiency by constructing larger freighter ships. The Panama Canal can handle ships carrying up to approximately 13,000 containers of goods. A canal through Nicaragua could be designed to accommodate ships that can carry several thousand more containers of goods at a time.

　　It is not clear that a canal in Nicaragua could consistently allow for larger ships to pass through. For this to happen, water levels in all parts of the canal need to be relatively. Currently, proposals for the canal include building it through lake Nicaragua, the largest lake in the region. But during droughts, the water level of lake Nicaragua becomes very low, and low water levels in lake Nicaragua naming that sometimes the water level will be too low for larger shirts to pass through.

　　Third, a canal through Nicaragua would be an opportunity to improve the environment. The builders of the canal have committed to compensate for environmental disruption caused by construction. For example, in order to offset the removal of trees in the path of the canal, the builders have agreed to plant a large number of trees in areas disrupted by the construction. In addition, they are also planning to replace trees in areas of Nicaragua where deforestation is already an extensive problem. These efforts to repair environmental damage will make significant improvements to the land.

　　Reforestation will not likely be enough to compensate for all the disruption caused by building the canal across Nicaragua. Nicar. Is an ecologically diverse country with several different types of ecosystems. And almost all of them will be altered by the construction of the canal. For example, the area affected by the canal construction contains different types of. Each with its own distinct ecosystem. Much diversity. To effectively measure the harm done to the environment and nearly impossible to repair the damage.