_江西成考网

10. Only then (   ) that he had left his key on his office. 

• A、he realized
  
  

• B、did he realize
  
  

• C、had he realized
  
  

• D、he had realized
  
  

53 .(    )

19. I'll do (   ) the guide said.

• A、as
  
  

• B、as if
  
  

• C、that
  
  

• D、all which