【托福写作机经】2025年4月23日托福考试回忆

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　　 主题：引进beaver到英国

　　河狸会建造水坝，堵塞河流，阻止鱼类通过。

　　河狸不会在每条河流中都建造水坝，而且它们挖掘的池塘有助于小鱼找到食物和躲避捕食者。

　　河狸挖洞会导致土壤流失。

　　土壤流失主要是因为水流太快，而河狸挖洞反而能使水流变慢，减少土壤流失。

　　河狸会啃食树木，破坏森林和生态系统。

　　树倒塌后，阳光可以照射到更多地面，促进花丛生长，吸引更多昆虫和动物，有益于生态系统。

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主题：sailing stone形成的原因

　　One such explanation is that the stones are pushed by the wind. Scientists have recorded strong winds in the playa, and when it rains, the playa's muddy floor becomes slick and slippery. Under such conditions, powerful gusts of wind could give the stones a considerable push. The reduced friction of the muddy ground would then allow the stones to slide long distances. Adding to the strength of this theory is the observation that the stones often travel parallel to the direction of the most common prevailing winds.

　First, it's true that the race track playa experiences powerful wins. But when the stones move, they leave rather deep grooves in the ground that dig into the valley floor. The grooves look like very deep tire tracks in the mud. This means the moving stones meet a lot of resistance. They're being pushed through the mud rather than just sliding or rolling on the surface. You would need a lot of force to push three hundred kilogram stones through the playa's muddy floor. And it is unlikely that even powerful winds have enough force to do that.

　　A second possible theory for the stones' movement involves ice formations. During the night, groundwater will occasionally seep up and form ice sheets on the ground. The ice sheets can trap stones within them. Ice sheets that form on sloping ground can start sliding slowly down the slope, pulled by gravity. Large and thick ice sheets would be able to drag along even heavy stones trapped within them. Over time the gradual sliding movement could transport the stones great distances.

　　What about the ice sheet theory? Well, for this theory to work. Large and thick ice sheets would have to form. There may be some ice occasionally forming in the race track. But the conditions there are not really favorable for large scale ice. First, it's a desert area, so there's only a small volume of groundwater available. And the small amount of ground water is not the only limiting factor. The temperature may drop below, freezing at night, but then it rises during the day. So the temperature typically does not stay below freezing long enough to allow the ice sheets to grow and thicken to the size needed to trap and carry the stones.

　　A third explanation is that people move the stones as part of an elaborate joke. In recent years, there have been reports of other unusual phenomena like crop circles, which were at first hard to explain but later turned out to be the work of people playing jokes. It is possible that the sailing stones have been moved around by people rather than by any natural forces.

　　And third, although the sailing stones may seem like someone's idea of a perfect practical joke. There isn't any evidence that people move them. Researchers have never found human footprints or the footprints of a pack animal like a horse that could drag the stones. And since we can tell from the stones tracks that they sometimes move during muddy periods. It would be impossible for any individuals to move the stones without leaving some kind of tracks themselves.

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主题：腓尼基水手是否绕非洲航行

　　First, it is highly unlikely that the Phoenician sailors possessed the necessary technology to sail around Africa as early as 600 B.C.E. The ships they built were small and held together only with crude wooden pegs. Also, the ships had only one simple square-shaped sail. While such technology might have been suitable to sail on the Mediterranean Sea near Phoenicia, it would not have been suitable for the long voyage in the open ocean around Africa.
First, it's true that Phoenicians used rather simple sailing technology, but that doesn't mean the voyage was impossible. In fact, recently in the twentieth century, some scientists and shipbuilders built a copy of an old Phoenician ship to see how capable it was of sailing long distances. They used exactly the same materials and techniques that were available to Phoenicians six hundred years BC. And guess what. The scientists successfully sailed this copy of an old ship around Africa, so Phoenician ships may have been good enough for a voyage like this.
Second, it also goes against what we know about Egyptian rulers of the time to suggest that Necho II ordered the expedition and hired the Phoenicians. Ancient Egyptians are understood to have been generally uninterested in exploring the world beyond their kingdom and the lands immediately surrounding it. Necho II would have had no reason to hire Phoenician sailors.

　First, it's true that Phoenicians used rather simple sailing technology, but that doesn't mean the voyage was impossible. In fact, recently in the twentieth century, some scientists and shipbuilders built a copy of an old Phoenician ship to see how capable it was of sailing long distances. They used exactly the same materials and techniques that were available to Phoenicians six hundred years BC. And guess what. The scientists successfully sailed this copy of an old ship around Africa, so Phoenician ships may have been good enough for a voyage like this.

　　Second, it's true that the ancient Egyptians were generally not interested in exploring areas outside Egypt, but Necho the Second was a rather different kind of king in this respect. For example, he was very interested in water transportation and started major projects to connect Egyptian rivers and seas through canals. Necho probably wanted to explore the possibilities of water transportation in general for trading purposes. He could have hired the Phoenician sailors to sail around Africa to help him discover new trading partners.
Third, it is possible that the account of a journey around Africa recorded in the ancient sources was just a story invented by sailors that later spread. It was not uncommon for people of the ancient world to make up stories and pass them off as truths, particularly when it had to do with the ocean. Stories of sea monsters and magical islands were also popular at the time, so in the same way, a story about a voyage around Africa could have been invented as well.

　　Second, it's true that the ancient Egyptians were generally not interested in exploring areas outside Egypt, but Necho the Second was a rather different kind of king in this respect. For example, he was very interested in water transportation and started major projects to connect Egyptian rivers and seas through canals. Necho probably wanted to explore the possibilities of water transportation in general for trading purposes. He could have hired the Phoenician sailors to sail around Africa to help him discover new trading partners.

　　Finally, the Phoenician sailors reported some facts that make it unlikely that they invented the story. They reported that when they sailed far to the south, they noticed that at midday, at twelve o'clock, the sun was in the northern part of the sky instead of the southern. Well, that's exactly what happens in the southern hemisphere. The sun appears in the northern part of the sky at midday, in contrast to what happens in the northern hemisphere, where the sailors were from. This information about the position of the sun would be hard to invent. The most likely explanation for it is that the Phoenicians had actually gone to the southern hemisphere and observed the sun themselves.

　　Finally, the Phoenician sailors reported some facts that make it unlikely that they invented the story. They reported that when they sailed far to the south, they noticed that at midday, at twelve o'clock, the sun was in the northern part of the sky instead of the southern. Well, that's exactly what happens in the southern hemisphere. The sun appears in the northern part of the sky at midday, in contrast to what happens in the northern hemisphere, where the sailors were from. This information about the position of the sun would be hard to invent. The most likely explanation for it is that the Phoenicians had actually gone to the southern hemisphere and observed the sun themselves.