Directions: There are 4 passages in this part. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should decide on the best choice and mark the corresponding letter on the Answer Sheet with a single line through the centre.

　　Passage One

　　Questions 21 to 25 are based on the following passage.

　　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 be 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 urbantraffic congestion (擁擠). One proposed solution to this problem is the automated highway system.

　　When the auto enters the highway system, a retractable (可伸縮的) 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 move-ments.

　　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 (蜂鳴器) that will warn him of his coming exit. It is estimated that an automated highway will be able to handle 10,000 vehicles per hour, compared with the 1,500 to 2,000 vehicles that can be carried by a present-day highway.

　　21. One significant improvement in the future car will probably be________.

　　A) its power source　　　　　　　　　　  C) its monitoring system

　　B) its driving system　　　　　　　　　　D) its seating capacity

　　22. What is the author's main concern?

　　A) How to render automobiles pollution-free.

　　B) How to make smaller and safer automobiles.

　　C) How to solve the problem of traffic jams.

　　D) How to develop an automated subway system.

　　23. What provides autos with electric power in an automated highway system?

　　A) A rail. 　　　　　　　　　　　　　　 C) A retractable arm.

　　B) An engine. 　　　　　　　　　　　　　D) A computer controller.

　　24. 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) keep in constant touch with the computer center

　　D) inform the system of his destination by phone

　　25. What is the author's attitude toward the future of autos?

　　A) Enthusiastic.　　　　　　　　　　C) Optimistic.

　　B) Pessimistic. 　　　　　　　　　　D) Cautious.