2018年备考英语职称考试综合类阅读理解素材9

 　　His nickname is Denny. He weighs 400 pounds; he is fearless and he never goes to sleep on the job. An ideal security guard? For many situations he may be. And if he's so good that you wish you had a dozen like him, just place your order. Denny is a robot guard.

　　Denny can detect, within a 150-foot radius, the presence of anything or anybody that shouldn't be there. Its swiveling (旋转) head contains microwave and infrared sensors that can detect people as well as smoke. In future editions the head will also contain sensors that can smell the weak smell of a human body.

　　A high-resolution TV camera in Denny's head is on at all time. When something unexpected comes into view, the TV transmitter switches on. Thus the human overseer (看管人) in the control center sees the sudden appearance of a picture on the monitor screen. At the same time the picture is automatically videotaped.

　　Normal speed of the robot guards is about one mile an hour, and they can even talk: 'you have been detected,' warns the voice from the clever guard. Denny is designed to patrol corridors and other areas after lock-down hours (of course, he can work round the clock when necessary), not to move among people. If, say, a prisoner does get near the corridor where he should not be, it'll immediately tell its base station by radio.

　　Denny has understandable limitations. He can't open doors or watch stairs, for example, or distinguish friend from enemy. Thus he will have to go about unarmed. And he won't be able to replace human security guards where people move about freely.