Cream and butter contain pretty much the same substances, so why cream should sour much faster has been a mystery. Both are emulsions—tiny globules (小球體) of one liquid evenly distributed throughout another. The difference lies in what’s in the globules and what’s in the surrounding liquid, says Brocklehurst, who led the investigation.

　　In cream, fatty globules drift about in a sea of water. In butter, globules of a watery solution are locked away in a sea of fat. The bacteria which make the food go bad prefer to live in the watery regions of the mixture. “This means that in cream, the bacteria are free to grow throughout the mixture,” he says.

　　When the situation is reversed, the bacteria are locked away in compartments (隔倉室) buried deep in the sea of fat. Trapped in this way, individual colonies cannot spread and rapidly run out of nutrients (養料). They also slowly poison themselves with their waste products. “In butter, you get a self-limiting system which stops the bacteria growing,” says Brocklehurst.

　　The researchers are already working with food companies keen to see if their products can be made resistant to bacterial attack through alterations to the food’s structure. Brocklehurst believes it will be possible to make the emulsions used in salad cream, for instance, more like that in butter. The key will be to do this while keeping the salad cream liquid and not turning it into a solid lump.

　　36. The significance of Brocklehurst’s research is that ________.

　　A) it suggested a way to keep some foods fresh without preservatives

　　B) it discovered tiny globules in both cream and butter

　　C) it revealed the secret of how bacteria multiply in cream and butter

　　D) it found that cream and butter share the same chemical composition

　　37. According to the researchers, cream sours fast than butter because bacteria ________.

　　A) are more evenly distributed in cream

　　B) multiply more easily in cream than in butter

　　C) live on less fat in cream than in butter

　　D) produce less waste in cream than in butter

　　38. According to Brocklehurst, we can keep cream fresh by ________.

　　A) removing its fat

　　B) killing the bacteria

　　C) reducing its water content

　　D) altering its structure

　　39. The word “colonies” (Line 2, Para. 4) refers to ________.

　　A) tiny globules

　　B) watery regions

　　C) bacteria communities

　　D) little compartments

　　40. Commercial application of the research finding will be possible if salad cream can be made resistant to bacterial attack ________.

　　A) by varying its chemical composition

　　B) by turning it into a solid lump

　　C) while keeping its structure unchanged

　　D) while retaining its liquid form

　　36. A 37. B 38. D 39.C 40. D

　　Amtrak (美國鐵路客運公司) was experiencing a downswing in ridership (客運量) along the lines comprising its rail system. Of major concern to Amtrak and its advertising agency DDB Needham, were the long-distance western routes where ridership had been declining significantly.] At one time, trains were the only practical way to cross the vast areas of the west. Trains were fast, very luxurious, and quite convenient compared to other forms of transportation existing at the time. However, times change and the automobile became America’s standard of convenience. Also, air travel had easily established itself as the fastest method of traveling great distances. Therefore, the task for DDB Needham was to encourage consumers to consider other aspects of train travel in order to change their attitudes and increase the likelihood that trains would be considered for travel in the west.

　　Two portions of the total market were targeted: 1) anxious fliers—those concerned with safety, relaxation, and cleanliness and 2) travel-lovers—those viewing themselves as relaxed, casual, and interested in the travel experience as part of their vacation. The agency then developed a campaign that focused on travel experiences such as freedom, escape, relaxation, and enjoyment of the great western outdoors. It stressed experiences gained by using the trains and portrayed western train trips as wonderful adventures.

　　Advertisements showed pictures of the beautiful scenery that could be enjoyed along some of the more famous western routes and emphasized the romantic names of some of these trains (Empire Builder, etc.). These ads were strategically placed among family-oriented

　　TV shows and programs involving nature and America in order to most effectively reach target audiences. Results were impressive. The Empire Builder, which was focused on in one ad, enjoyed a 15 percent increase in profits on its Chicago to Seattle route.

　　31. What’s the author’s purpose in writing this passage?

　　A) To show the inability of trains to compete with planes with respect to speed and convenience.

　　B) To stress the influence of the automobile on America’s standard of convenience.

　　C) To emphasize the function of travel agencies in market promotion.

　　D) To illustrate the important role of persuasive communication in changing consumer attitudes.

　　32. It can be inferred from the passage that the drop in Amtrak ridership was due to the fact that ________.

　　A) trains were not suitable for short distance passenger transportation

　　B) trains were not the fastest and most convenient form of transportation

　　C) trains were not as fast and convenient as they used to be

　　D) trains could not compete with planes in terms of luxury and convenience

　　33. To encourage consumers to travel by train, DDB Needham emphasized ________.

　　A) the freedom and convenience provided on trains

　　B) the practical aspects of train travel

　　C) the adventurous aspects of train trips

　　D) the safety and cleanliness of train trips

　　34. The train ads were placed among family-oriented TV programs involving nature and America because ________.

　　A) they could focus on meaningful travel experiences

　　B) they could increase the effectiveness of the TV programs

　　C) their profits could be increased by some 15 percent

　　D) most travel-lovers and nervous fliers were believed to be among the audiences

　　35. According to the passage, the Empire Builder enjoyed an increase in ridership and profits because ________.

　　A) the attractiveness of its name and route was effectively advertised

　　B) it provided an exciting travel experience

　　C) its passengers could enjoy the great western outdoors

　　D) it was widely advertised in newspapers and magazines in Chicago and Seattle

　　31. D 32. B 33.C 34. D 35. A