48. It can be inferred from the passage that (   ). 

• A、when one is in a bad mood, he or she may not work very well
  
  

• B、the best way to overcome a bad mood is to talk to oneself
  
  

• C、some drugs are more effective than physical exercises
  
  

• D、taking drugs is at the risk of being poisonous
  
  

54. (   )

41. According to the passage, some doctors believe it is true that (   ). 

• A、you are healthy if cold-water swimming turns your skin color blue
  
  

• B、cold-water swimming causes more heart attacks in summer than in winter
  
  

• C、cold-water swimming can make the body temperature dangerously high
  
  

• D、Polar Bears are bears swimming in freezing water