# American salt marshes - 科目：雅思听力真题（Part 4） - 考频：中频 - 最近考试：2023.11.18/2021.8.14 - 题目数：10 - 来源页：https://www.yaquan.site/paper/0219af4c-4536-4e62-8a6b-5e625e2789be（在线机考练习与音频请访问该页面） - 数据更新：2026-10-29 ## 题目原文 00:00:00,220 Part four. 00:00:02,200 You will hear part of a lecture about American salt marshes, which are areas of low land found near the sea. First, you have some time to look at questions thirty-one to forty. 00:01:14,120 Now listen carefully and answer questions thirty-one to forty. 00:01:21,560 Right. This morning, I want to give you a brief introduction to a different kind of habitat, American salt marshes. And then we'll examine a particular inhabitant of the marsh, the horseshoe crab. Okay, so what are the defining features of a salt marsh to begin with? 00:01:41,860 Well, salt marshes are found on the coast in various parts of the USA. They are really areas between land and water. Obviously, these are very wet areas and the salinity, that's the amount of salt in the water, ranges from ocean strength to almost fresh. In other words, very low indeed. 00:02:06,060 And the salt marshes are affected by daily changes in sea levels. The sea might wash in over them as frequently as twice a day, so the habitat is constantly changing. The amount of salt in the water rises and falls, as does the depth and warmth of the water. 00:02:26,360 We'll be having a detailed look at the horseshoe crab in a moment, but marshes provide plentiful food for other creatures that feed there too, such as worms and shrimps. This food comes in the form of plants that thrive there. 00:02:43,100 Interestingly enough, two hundred years ago, the flow of water in marshland in the United States was controlled so that rice could be grown there. Little is grown there today, but fifteen percent of coastal marshes are enclosed artificially in order to attract wild birds to the area, and we'll be examining those, too. 00:03:11,400 But before looking at the wildlife, there are a few political issues to make you aware of. 00:03:18,400 There are always controversial issues when humans decide to make changes to natural habitats. During the past twenty years, many objections have been voiced to the building of artificial earth walls, or dikes to use the correct term, on salt marshes to control the natural flow of seawater. 00:03:41,00 Since the walls restrict the movement of high volumes of water, this means that the natural habitat of local aquatic life is reduced. 00:03:50,420 And because the water is shallower, the temperature of the water may rise significantly during periods of low rainfall. 00:03:58,880 In addition, although the insects are very happy there, many people are unhappy with the dikes. This isn't because they distract from the natural beauty of the landscape, but because their presence means it's more difficult for walkers who appreciate the marshes to go where they want. 00:04:19,420 There is controversy over the different values placed on the resources of the marshes. Some people would like to see them used more fully for hunting, while others would like to see business permits granted to allow for further development. 00:04:35,940 Interestingly, in the mid-twentieth century, marshes were not thought of as valuable at all, and over half of the salt marshes in the USA were destroyed at that time. 00:04:47,440 In the main, this was due to filling the marshes to create more land for housing developments and to control the mosquito population. 00:04:57,040 However, state laws now do reflect the importance and growing appreciation of marshes, not only as natural habitats, but also because they provide a natural barrier against storm damage and therefore limit the amount of land lost to the sea. 00:05:16,560 Right. 00:05:18,040 We'll be debating some of those issues in the seminars, but let's now turn our attention to the horseshoe crab, which is the focus of our study this morning. 00:05:28,480 Horseshoe crabs have changed very little in the last three hundred and fifty million years. I find them interesting in many ways because they are, in fact, distant relatives of the spider and not crabs at all. They look quite dangerous. In fact, they are absolutely harmless. 00:05:48,560 The horseshoe crab's main diet is one of shellfish, but they will eat worms too. 00:05:55,260 The crab places its food near its mouth in the center of its underside, where its legs are attached, and grinds and crushes it there. It has five pairs of legs. 00:06:08,960 The female lays between two hundred and three hundred eggs and comes ashore to do that. 00:06:15,820 This process takes place in spring before the sand heats up in the summer months. 00:06:22,100 Right. What I'm gonna do now is show you some photos. 00:06:30,280 That is the end of part four. You now have forty-five seconds to check your answers to part four. ## 题目与答案 ### 31. The salt content in marshes can be as high as that of the 31_____ . The salt content in marshes can be as high as that of the 31_____ . **答案**：ocean 原文定位：the salinity, that's the amount of salt in the water, ranges from ocean strength to almost fresh 同义替换：「salt content」↔「the amount of salt in the water」；「as high as」↔「strength」 ### 32. At different times of the day, there are changes in salinity and in the 32_____ and warmth of the water. At different times of the day, there are changes in salinity and in the 32_____ and warmth of the water. **答案**：depth 原文定位：The amount of salt in the water rises and falls, as does the depth and warmth of the water 同义替换：「changes in salinity」↔「The amount of salt in the water rises and falls」 ### 33. Animals such as worms and shrimps feed on the 33_____ that grow in the marsh. Animals such as worms and shrimps feed on the 33_____ that grow in the marsh. **答案**：plants 原文定位：marshes provide plentiful food for other creatures that feed there too, such as worms and shrimps. This food comes in the form of plants that thrive there 同义替换：「Animals」↔「creatures」；「feed on」↔「food comes in the form of」；「grow」↔「thrive」 ### 34. Marshland in the US has been used in the past for 34_____ cultivation. Marshland in the US has been used in the past for 34_____ cultivation. **答案**：rice 原文定位：two hundred years ago, the flow of water in marshland in the United States was controlled so that rice could be grown there 同义替换：「has been used in the past」↔「two hundred years ago」；「cultivation」↔「grown」 ### 35. 35 The speaker says that one result of erecting artificial walls in salt marshes is that 35 The speaker says that one result of erecting artificial walls in salt marshes is that - water levels can get too high - wildlife has less space - water quality is difficult to control **答案**：wildlife has less space 原文定位：Since the walls restrict the movement of high volumes of water, this means that the natural habitat of local aquatic life is reduced 同义替换：「wildlife」↔「local aquatic life」；「less space」↔「habitat of local aquatic life is reduced」 ### 36. 36 Some people have complained about the building of dikes because 36 Some people have complained about the building of dikes because - access for walkers is reduced - the insect population has increased - the natural beauty of the area is affected **答案**：access for walkers is reduced 原文定位：This isn't because they distract from the natural beauty of the landscape, but because their presence means it's more difficult for walkers who appreciate the marshes to go where they want 同义替换：「dikes」↔「presence」；「is reduced」↔「more difficult」 ### 37. 37 In the 20th century, a large proportion of marshes in America became 37 In the 20th century, a large proportion of marshes in America became - salt extraction sites - residential areas - protected insect reserves **答案**：residential areas 原文定位：Interestingly, in the mid-twentieth century, marshes were not thought of as valuable at all, and over half of the salt marshes in the USA were destroyed at that time;In the main, this was due to filling the marshes to create more land for housing developments and to control the mosquito population 同义替换：「a large proportion」↔「over half」；「residential areas」↔「housing developments」 ### 38. 38 There are now laws which help to prevent 38 There are now laws which help to prevent - the erosion of soil - the building of more walls - the extinction of sea life **答案**：the erosion of soil 原文定位：state laws now do reflect the importance and growing appreciation of marshes;they provide a natural barrier against storm damage and therefore limit the amount of land lost to the sea 同义替换：「help to prevent」↔「limit the amount of land lost」；「erosion of soil」↔「land lost to the sea」 ### 39. The Horseshoe Crab Related to: spider Most common food: 39_____ The Horseshoe Crab Related to: spider Most common food: 39_____ **答案**：shellfish 原文定位：The horseshoe crab's main diet is one of shellfish, but they will eat worms too 同义替换：「Most common food」↔「main diet」 ### 40. Time of year when female lays eggs: 40_____ Time of year when female lays eggs: 40_____ **答案**：spring 原文定位：The female lays between two hundred and three hundred eggs and comes ashore to do that. This process takes place in spring before the sand heats up in the summer months --- 以上内容由鸭圈雅思真题库（www.yaquan.site）提供，收录近期雅思考试真题回忆，支持在线机考模式免费练习。