30. Although Gutenburg developed his printing press with a limited use in mind , the cultural effects of mass printing have been ( )

54、( ), he always tries his best to complete it on time.

53、He's( )as a "bellyacher"-----he's always complaining about something.

52、If you have really been studying English for so long, it's about time you( )able to write letters in English.

51、He( )unwisely, but he was at least trying to do something helpful.

50、I've never been to Lhasa. but that's the city( ).

49、There ought to be less anxiety over the perceived risk of mountain climbing than( ) in the public mind today.

48、It is not so much the language( )the cultural background that makes the book difficult to understand.

47、Fat cannot change into muscle( )muscle changes into fat.

46、Professor Johnson is said( )some significant advance in his research in the past year.

45、The three men tried many times to sneak across the border into the neighboring country,( )by the police each time.