27.The teachers’union（ ）a lawsuit against the district calling for repairing “deplorable” school conditions.

63.You must let me have the annual report without（ ）by ten o’clock tomorrow morning.

62.While he was in Beijing, he spent all his time（ ）some important museums and buildings.

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

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

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

58.We should make a clear（ ）between “competent” and “proficient” for the purpose of our discussion.

57.The chances of a repetition of these unfortunate events are（ ）indeed.

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

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

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