Being a physician who flies much often, a lot of my time is spent on planes listening for that fearful “Is there a doctor  41  ?” announcement. I’ve been called only once — for a woman who had only fainted. But the  42   made me quite curious about how  43   this kind of thing happens. I wondered what I would do if  44   with a real mid-air medical emergency — without access  45   a hospital staff and the usual emergency equipment. So  46   the New England Journal of Medicine last week  47   a study about in-flight medical events, I read it with  48  .

Thestudy estimated there are a(n)   49   of30 in-flight medical emergencies on U.S. flights every day. Most of them aren’t  50  ;fainting and dizziness are the most frequent complaints.   51  13%of them (roughly four per day) are serious enough to   52   a pilot to change course. The most common ofthe serious emergencies   53   heart trouble, strokes, and difficultbreathing.

In fact, some riders are   54  .For starters, cabin pressures at high altitudes are set at about   55   they would be if you lived at 5,000 to 8,000feet above sea level. Most people   56   tolerate the pressures pretty easily, but riderswith heart disease may experience chest pains as a result of the   57   amount of oxygen flowing through their blood.   58   common in-flight problem is deep venousthrombosis (静脉血栓).   59   happens,don’t panic. Things are getting better on the in-flight-emergency front. Thanksto more recent laws, flights with at   60   one attendant are starting to install (安装) emergency medicalequipment to treat heart attacks.

41. A. on abroad           B. on board             C. on aboard             D. go aboard

42. A. affair                 B. condition            C. disaster             D. incident 

43. A. soon               B. often                  C. long                 D. many

44. A. faced               B. treated                C. identified             D. provided 

45. A. by                   B. for                      C. to                     D. through

46. A. when               B. since                C. before                 D. while

47. A. collected           B. discovered            C. published             D. conducted

48. A. patience               B. joy                    C. sorrow                 D. interest

49. A. amount               B. average                C. sum                 D. number

50. A. significant           B. heavy                C. common             D. serious

51. A. For               B. Or                      C. So                 D. But

52. A. require               B. inspire                   C. engage                 D. command

53. A. contain               B. imply                C. include             D. show    

54. A. enjoyable           B. stressful             C. stimulating             D. boring 

55. A. who               B. which                C. that                 D. what

56. A. should                  B. must                C. can                 D. need

57. A. reduced                    B. increased            C. raised                 D.produced

58. A. Any               B. Another                 C. Other                  D. One

59. A. Whatever              B. Wherever            C. Whenever          D.Whichever

60. A. most                   B. best                C. worst                    D. Least