【正文】 esearch indicates that positive reinforcement motivates and has a greater effect on learning than criticism. Again, criticism can create high levels of stress, which can lead to burnout. 　　本文主題在于強調(diào)積極強化對于年輕運動員的作用。前面的部分為鋪墊，而在文章末尾才給出主題句。 　　例三：主題句在文章中間（） 　　Some pessimistic experts feel that the automobile is bound to fall into disuse. They see a day in the nottoodistant 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 bee smaller, safer, and more economical, and should not be powered by the gasoline engine. The car of the future should be far more pollutionfree than present types. 　　Regardless of its power source, the auto in the future will still be the main problem in urban traffic 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 bee electrically powered from the system, and control of the vehicle will pass to a central puter. The puter 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 puter 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 ing exit. It is estimated that an automated highway will be able to handle 10,000 vehicles per hour, pared with the 1,500 to 2,000 vehicles that can be carried by a presentday highway. 　　本文頭兩段指出了不同人對于汽車的前途的不同看法，在第三段，即文章中間才給出主題句，講解決城市交通堵塞的一個方法是自動高速公路系統(tǒng)。后面兩段具體介紹自動高速公路系統(tǒng)是如何工作的。 　　請讀下面的文章并且找到主題句，做出主旨題。 　　Exercise 1 　　The biggest safety threat facing airlines today may not be a terrorist with a gun, but the man with the portable puter in business class. In the last 15 years, pilots have reported well over 100 incidents that could have been caused by electromagnetic interference. The source of this interference remains unconfirmed, but increasingly, experts are pointing the blame at portable electronic devices such as portable puters, radio and cassette players and mobile telephones. 　　RTCA, an organization which advises the aviation（航空）industry, has remended that all airlines ban（禁止）such devices from being used during “critical” stages of flight, particularly takeoff and landing. Some experts have gone further, calling for a total ban during all flights. Currently, rules on using these devices are left up to individual airlines. And although some airlines prohibit passengers from using such equipment during takeoff and landing, most are reluctant to enforce a total ban, given that many passengers want to work during flights. 　　The difficulty is predicting how electromagnetic fields might affect an aircraft’s puters. Experts know that portable devices emit radiation which affects those wavelengths which aircraft use for navigation and munication. But, because they have not been able to reproduce these effects in a laboratory, they have no way of knowing whether the interference might be dangerous or not. 　　The fact that aircraft may be vulnerable（易受損的）to interference raises the risk that terrorists may use radio system in order to damage navigation equipment. As worrying, though, is the passenger who can’t hear the instructions to turn off his radio because the music’s too loud. 　　Q: The passage is mainly about . 　　A) a new regulation for all airlines 　　B) the defects of electronic devices 　　C) a possible cause of aircraft crashes 　　D) effective safety measures for air flight 　　【題目譯文】這篇文章是關(guān)于 　　【答案解析】C。從每段的第一句話可知文章講述電磁干擾對于飛機安全的影響和飛行事故的可能原因。 　　Exercise 2 　　Believe it or not, optical illusion（錯覺）can cut highway crashes. 　　Japan is a case in point. It has reduced automobile crashes on some roads by nearly 75 percent using a simple optical illusion. Bent stripes, called chevrons（人字形）painted on the roads make drivers think that they are driving faster than they really are, and thus drivers slow down. 　　Now the American Association Foundation for Traffic Safety in Washington D. C. is planning to repeat Japan’s success. Starting next year, the foundation will paint chevrons and other patterns of stripes on selected roads around the country to test how well the patterns reduce highway crashes. 　　Excessive speed plays a major role in as much as one fifth of all fatal traffic accidents, according to the foundation. To help reduce those accidents, the foundation will conduct its tests in areas where speedrelated hazards are the greatest—curves, exit slopes, traffic circles, and bridges. 　　Some studies suggest that straight, horizontal bars painted across roads can initially cut the average speed of drivers in half. However, traffic often returns to full speed within months as drivers bee used to seeing the painted bars. 　　Chevrons, scientists say, not only give drivers the impression that they are driving faster than they really are but also make a lane appear to be narrower. The result is a longer lasting reduction in highway speed and the number of traffic accidents. 　　Q: The passage mainly discusses . 　　A) a new way of highway speed control 　　B) a new pattern for painting highways 　　C) a new approach to training drivers 　　D) a new type of optical illusion 　　【題目譯文】文章主要討論了 。 　　【答案解析】A。文章以日本和美國在高速公路