58. A经常和课程连用的，表示难度大的形容词包括 'demanding', 'tough', 'hard' or 'difficult'.

55. A　 56. A　 57. A

54. be on (or at) the tip of one's tongue 就在嘴边，差点被想起；be on the point of 正要(去做某事)。

53. B go under 破产，失败。fall through 也有“失败”之意，但多半指计划、想法等“落空”；fall out 发生，闹翻，吵架。

52. D on the side(=in addition to a main thing) 额外；作为兼职;on the rise(作表语)在上升；on the spot 现场；on the decline (做表语)在下降.

51. A on the alert (=alert; watchful; careful) 警惕，小心：Drivers must be on the alert for traffic signals. (=Drivers must be especially careful to see signals when driving a car.) (司机必须密切注视交通信号。)out of control 失去控制；on guard站岗；in vain 徒劳，无效。

50. D yield to:屈服于;投降让步(经常有比较灵活的译法)。如:The disease yielded to treatment.(=The disease was cured as the result of treatment.)(这病经过治疗已减轻或治愈。)appeal to向......呼吁;stick to(=keep to)坚持

49. A secure 与 acquire 钧有“得到”的含义，但 secure vt. 此处的意思是(=succeed in getting sth. for which there is a great demand)“获得(所需之物)”.acquire“获得，求得”，尤其指由于自己的努力，能力，技术而使原有的东西变得更多，并表示一经求得，即成永久的所有物。

48. D confidential(=spoken or written in secret) 机密的，应保密的:The information is confidential. special 专门的，专用的: a special car(专车).individual 个别的，单个的。secretive(=fond of keeping secrets) 爱保密的，守口如瓶的.

47. D run off(=produce with a printing press or duplicating machine)印刷，复印; write off报废，勾销。give out分发，发出。send in 呈报，递交，送上。