51.(      )

39. The policeman was there (   ). 

• A、to meet Mr. Brown, his uncle
  
  

• B、to ask Mr. Brown to go and see his uncle
  
  

• C、to ask Mr. Brown to mark his name on his door
  
  

• D、to see Mr. Brown about some trouble at the bank
  
  

46. We'd better have our meals (   ). 

• A、at the same time each day
  
  

• B、when our work is over
  
  

• C、when the meal is not hot
  
  

• D、when everyone is at home