16.“It’s a shame that the city official should have gone back on his word.” The modal auxiliary SHOULD expresses ( ).

64、The diversity of tropical plants in the region represents a seemingly ( ) source of raw materials, of which only a few have been utilized.

63、Rite of Passage is a good novel by any standards;( ), it should rank high on any list of science fiction.

62、In the present economic ( ) we can make even greater progress than previously.

61、We should make a clear ( ) between 'competent' and 'proficient' for the purposes of our discussion.

60、The chances of a repetition of those unfortunate events are ( ) indeed.

59、This project would ( ) a huge increase in defense spending.

58、In winter drivers have trouble stopping their cars from ( ) on icy roads.

57、The motorist had to ( ) to avoid knocking the old woman down in the middle of the road.

56、When you're driving on a motorway, you must obey the signs telling you to get into the right ( )

55、Many people are ( ) to insect bites, and some even have to go to hospital.