American salt marshes

文章大意

讲座介绍美国沿海盐沼这种介于陆地与海洋之间的湿地生境，盐度从海水到近乎淡水，受潮汐每日变化影响。盐沼为蠕虫、虾等生物提供食物，重点提到马蹄蟹（鲎）。还谈及历史上引水种稻、如今15%盐沼被围垦吸引野鸟，以及修建堤坝控制海水引发的争议。

题目与答案

1. 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」

2. 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」

3. 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」

4. 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」

5. 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」

6. 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」

7. 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」

8. 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」

9. 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」

10. 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