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III. Reading Comprehension     
Section A
Directions: For each blank in the following passage there are four words or phrases marked A, B, C and D.  Fill in each blank with the word or phrase that best fits the context.
Your cell phone holds secrets about you. Besides the names and   50   that you’ve programmed into it, traces of your DNA remain on it, according to a new study.
　　DNA is genetic material that appears in every cell. Like your fingerprint, your DNA is unique to you   51   you have an identical twin. Scientists today routinely analyze DNA in blood, saliva (唾液), or hair   52   behind at the scene of a crime. The results often help detectives identify   53   and their victims. Your cell phone can   54   more about you than you might think.
　　Meghan J. McFadden, a scientist at McMaster University1in Hamilton, Ontario, heard about a crime in which the suspect（嫌疑犯）bled onto a cell phone and later dropped the   55  . This made her wonder whether traces of DNA remained on cell phones ___ even when no blood was involved.　    56   she and colleague Margaret Wallace of the City University of New York analyzed the flip-open phones(翻盖手机) of 10 volunteers. They used swabs(药签) to collect   57   traces of the users from two parts of the phone: the outside, where the user holds it, and the   58  , which is placed at the user’s ear.
The scientists scrubbed the phones using a solution made mostly of alcohol. The aim of washing was to   59   all detectable (可查明的) traces of DNA. The owners got their phones back for another week.   60   the researchers collected the phones and repeated the swabbing of each phone once more.
The scientists discovered DNA that   61   to the phone’s owner on each of the phones. Better samples were collected from the outside of each phone, but those swabs also   62    DNA of other people who had apparently also handled the phone.   63  , DNA showed up even in swabs that were taken immediately after the phones were scrubbed. That suggests that washing won’t remove all traces of evidence from a criminal’s device. So cell phones can now be added to the   64   of clues that can settle a crime-scene investigation.
50. A. secrets　                B. music                      C. numbers                  D. films
51. A. because                   B. unless                      C. although                  D. if
52. A. kept                        B. dropped                   C. stayed                      D. left
53. A. criminals                 B. clues                   C. witnesses                 D. policemen
54. A. reveal                     B. convince                  C. acquire                     D. value
55. A. document                 B. paper                             C. card                        D. device
56. A. However                 B. But                          C. So                          D. For
57. A. invisible                  B. non-existent             C. missing                   D. apparent
58. A. microphone           B. keys                        C. screen                     D. speaker
59. A. preserve                   B. revise                      C. remove                    D. protect
60.   A. Then                        B. Thus                       C. Meanwhile               D. Otherwise
61.   A. stuck                       B. belonged                 C. happened                 D. contributed
62. A. took in                    B. mixed with              C. picked up                D. gave out
63.   A. Generally                B. Shortly                    C. Disappointedly         D. Surprisingly
64. A. explanation              B. list                          C. book                       D. discovery