American Salt Marshes · Part 4 · 第 35–38 题

Choose the correct letter, A, B or C.

1. 35

   The speaker says that one result of erecting artificial walls in salt marshes is that

   Awater levels can get too high.Bwildlife has less space.Cwater quality is difficult to control.
2. 36

   Some people have complained about the building of dikes because

   Aaccess for walkers is reduced.Bthe insect population has increased.Cthe natural beauty of the area is affected.
3. 37

   In the 20th century, a large proportion of marshes in America became

   Asalt extraction sites.Bresidential areas.Cprotected insect reserves.
4. 38

   There are now laws which help to prevent

   Athe erosion of soil.Bthe building of more walls.Cthe extinction of sealife.