Question

7. The factories along the river greatly polluted the water supply of the residents nearby,which        had a bad effect on their health.

   A. in vain   B. in return

   C. in turn   D. in surprise

Answer 1

7. C题意为:"河流沿岸的工厂污染了附近居民的水源，继而对居民的身体健康产生了坏的影响。"in turn意为"转而，反过来"；in return意为"作为回报"。