单项选择题
| Villages in developing countries often lack many things. Books, clean water, electricity. These shortages are (36) to (37) . But a (38) kind of shortage is not easy to see. That is a shortage of (39) Many villages have no doctors, engineers or scientists. They have no one who know (40) to treat unusual medical problems or design a new expert system. There’s a way to ease these problems. They can do it with (41) . In the past few years, computer scientists around the world (42) (43) they call expert systems. An expert system is a special kind of computer program. In some (44) , it can take the place of a human expert. For example, an expert in (45) system can help (46) a sick person. A question appears on the computer screen, "Is the person hot7" You tell the computer either yes or no. The computer asks (47) questions. "Has the person lost any blood" Can the person move normally" You (48) . The computer continues to ask questions (49) it has enough (50) to make a decision. Then it tells what (51) or other treatment is needed. In this way the expert system takes the place of a (52) . Another kind of expert system takes the place of an engineer. It (53) the flow of water in the river. It tells if a dam can be built (54) the river. It also tells (55) electricity can be produced. Still other kinds of expert systems help solve problems for farmers and owners of small businesses. |