46. C) Help them build a positive attitude towards life.
47. A) Earn more money.
48. C) How long its positive effect lasts.
49. D) Their communication with others improved.
50. A) Find financial support.
51. What happened to Darwin's letter in the 1970s?
B) It was stolen more than once.
答案出处：“We realized in the mid-1970s that it was missing,”…. likely taken by an intern (实习生)”… “The intern likely took the letter again once nobody was watching it.”
52. What did the FBI do after the recovery of the letter?
A) They proved its authenticity.
答案出处：Their art crime team recovered the letter but were unable to press charges because the time of limitations had ended. The FBI worked closely with the Archives to determine that the letter was both authentic and definitely Smithsonian’s property.
53. What is Darwin's letter about?
D) His acknowledgement for help from a professional.
答案出处：The letter was written by Darwin to thank an American geologist, Dr. Ferdinand Vandeveer Hayden, for sending him copies of his research into the geology of the region that would become Yellowstone National Park.
54. What will the Smithsonian Institution Archives do with the letter according to Kapsalis?
D) Make it available online.
After it is repaired, we will take digital photos of it and that will be available online.
55. What has the past half century witnessed according to Kapsalis?
B) Radical changes in archiving practices.
“Archiving practices have changed greatly since the 1970s,”says Kapsalis, “and we keep our high value documents in a safe…”