39. _____ men have learned much from the behavior of animals is brand-new.
A. That                 
B. Those              
C. What            
D. Whether

40. A man escaped from the prison last night. It was a long time ____ the guards discovered what had happened.
A. before              
B. until                  
C. since            
D. when

41. Government cannot operate effectively ____ it is free from such interference.
A. so long as         
B. so that              
C. unless           
D. because

42. No matter how frequently ____, the works of Beethoven always attract large audiences.
A. performing                                  
B. performed
C. to be performed                           
D. being performed

43. ____ quit recently, most mothers in Britain did not take paid work outside the home.
A. Before              
B. Until                
C From             
D. Since

44. In some countries, ____ is called “equality” does not really mean equal rights for all people.
A. which                
B. what                
C. that           
D. one

45. Liquids are like solids ____ they have a definite volume.
A. in that                
B. for that            
C. with that   
D. at that
 


参考答案:
39.A    40.C   41.C
42.b  No matter how引导的是让步状语从句，其主语the works和助动词are被省略。      
43.B    44.B   45.A