2010年中级英语考试考试试卷.docVIP

PAGE 第 PAGE 2 页 2010年中级任职资格外语考试试卷 英语 （120分钟内完成） 单位 ： 姓名： 题 号 一 二 三 总分 1 2 1 2 1-5 得 分 阅读理解（每题3分，共30分） 短文1（15分） A microphone is a device for changing sound into electrical signals. These signals can then be broadcast through the air or sent over wires to distants points where they can be changed back into sound again.Radio and television stations use microphones to pick up the sounds they want to broadcast. Microphones serve a similar purpose in public address systems and in making sound recordings and the sound portion of motion pictures. Telephones also use microphones for transmission. Microphones can be divided into two groups,according to how they respond to sound waves.These groups are the pressure-type microphones and velocity-type microphones. Pressure-type microphones include the condenser or capacity microphone, the moving coil or dynamic microphone, the crystal microphone,and the carbon microphone. In the condenser microphone, the vibrating diaphragm changes the capacitance of a condenser. The moving coil microphone works just opposite to the way a loudspeaker works. In the crystal microphone, the vibrating diaphragm twists a piezoelectric crystal,producing an electric current. A carbon microphone works like a telephone transmitter. The velocity-type of microphone has a light ribbon of aluminum foil loosely held in a strong magnetic field. Sound waves make the ribbon vibrate. The movement of the ribbon in the magnetic field generates varying amounts of current in the ribbon. This produces an electric signal. Microphones have been developed for many uses.Broadcasters and entertainers often wear personal microphones called lavalier or lapel microphones. Wireless microphones have been developed so that entertainers can be free to move about the stage without worrying about tripping over wires. Several people have been credited with the invention of the microphone, including the American inventor Thomas Alva Edison. The fir