题目

在△ABC中，内角所对的边分别为，已知. （1）求证：成等比数列；         （2）若，求△的面积S. 答案：解：（1）由已知得：， ， ， 再由正弦定理可得：， 所以成等比数列.                                           （2）若，则， ∴， ， ∴△的面积.                    三.完形填空 Seventeen-year-old Rivertown teenager, John Janson, was honoured at the Lifesaver Awards last night for carrying out lifesaving first aid on his neighbour after a shocking knife  36 . John was presented with his award at a ceremony(仪式) which recognized the  37  of ten people who have saved the life of  38  person. John had been studying in his room when he heard  39 . When he and his father rushed outside, they  40  that Anne Slade, mother of three, had been stabbed  41  with a knife by her ex-boyfriend. The man ran from the  42  and left Ms Slade lying in her front garden  43 very heavily. Her hands had almost been cut from her body. It was John’s quick  44  and knowledge of first aid that saved Ms Slade’s life. He immediately asked a number of  45  people for bandages, but when nobody could put their hands on any, his father got some tea towels(毛巾) and  46  from their house. John used these to dress the most severe  47  to ms Slade’s hands. He slowed the bleeding by applying pressure to the wounds until the  48  and ambulance arrived. “I’m  49  of what I did but I was just doing what I had been  50 ,” John said. John had taken part in the Young Lifesaver Scheme at his high school. When  51  John. Mr Alan Southerton, Director of the Young Lifesaver Scheme said, “There is no doubt that John’s quick thinking and the first aid  52  that he learnt at school saved Ms Slade’s life. This shows that a simple knowledge of first aid can make a real  53 .” John and nine other Life Savers also attended a  54  reception yesterday hosted by the Prime Minister before  55  their awards last night. 36.A. show                 B. attack                    C. fight                      D. defend 37.A. bravery             B. courage                  C. achievements           D. progress 38.A. any other           B. another                   C. the other                 D. others 39.A. quarrelling                B. arguing                  C. shouting                 D. screaming 40.A. realized              B. believed                  C. thought                   D. discovered 41.A. repeatedly         B. rudely                    C. frequently               D. gradually 42.A. home                 B. place                      C. scene                      D. garden 43.A. shaking              B. struggling               C. bleeding                 D. crying 44.A. action                       B. operation                       C. experience              D. request 45.A. several               B. nearby                    C. familiar                  D. curious 46.A. water                 B. tape                        C. instrument              D. luggage 47.A. damages             B. pains                      C. injuries                   D. cuts 48.A. neighbours                B. children                   C. doctor                    D. police 49. A. proud               B. fond                     C. sure                        D. tired 50.A. expected            B. taught                     C. encouraged             D. educated 51.A. praising             B. referring to             C. talking with            D. congratulating 52.A. skills                 B. instructions             C. treatments                D. methods 53.A. discovery           B. contribution            C. difference               D. choice 54.A. recent                       B. public                     C. private                    D. special 55.A. giving                B. remembering           C. announcing             D. receiving