因果条件题

　　passage 6
　　Some pessimistic experts feel that the automobile is bound to fall into disuse. They see a day in the not-too-distant future when all autos will b6 abandoned and allowed to rust. Other authorities,however, think the auto is here to stay. They hold that the car will remain a leading means of urban travel in the foreseeable future.
　　The motorcar will undoubtedly change significantly over the next 30 years. It should become smaller，safer，and more economical, and should not be powered by the gasoline engine. The car of the future should be far more pollution-free than present types.
　　Regardless of its power source，the auto in the future will still be the main problem in urban traffic congestion (拥挤)? One proposed solution to this problem is the automated highway system.
　　When the auto enters the highway system,a retractable (可伸缩的)arm will drop from the auto and make contact with a rail，which is similar to those powering subway trains electrically. Once attached to the rail,the car will become electrically powered from the system,and control of the vehicle will pass to a central computer. The computer will then monitor all of the car's movements.
　　The driver will use a telephone to dial instructions about his destination into the system. The computer will calculate the best route,and reserve space for the car all the way to the correct exit from the highway. The driver will then be free to relax and wait for the buzzer (蜂鸣器)that will warn him of his coming exit, ft is estimated that an automated highway will be able to handle 10,000 vehicles per hour, compared with the X, 500 to 2 ,000 vehicles that can be carried by a present-day highway.

　　6. In an automated highway system, all the driver needs to do is_?
　　A. keep in the right lane
　　B. wait to arrive at his destination
　　C. keeping constant touch wit^i the computer center
　　D. inform the system of his destination by phone

讲解答案

　　讲解答案：
　　D根据文章最后一段的内容：司机用电话把他的目的地告诉系统(The driver will use a telephone to dial instructions about his destination into the system)，计算机就会计算出最佳的路线，D 项是正确的。