Recognize the main idea and facts

THIS passage is from the CET-4 test of January, 2000. Read it and try to give the correct answers to the multiple-choice questions.

Why does cream go bad faster than butter? Some researchers think they have the answer, and it comes down to the structure of the food, not its chemical composition ? a finding that could help rid some processed foods of chemical preservatives.

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 (小球体) of one liquid evenly distributed throughout another. The difference lies in what's in the globules and what's in the surrounding liquid, says the leader of the investigation, a man named Brocklehurst.

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 that 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 (隔仓室) buried deep in the sea of fat. Trapped in this way, individual colonies cannot spread and rapidly run out of nutrients (养料). They also slowly poison themselves with their waste products. "In butter, you get a self-limiting system which stops the bacteria growing," says the researcher.

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



1. 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

2. According to the researchers, cream sours faster 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

3. 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

4. The word "colonies" (Line 3, Para.4) refers to ________.

A) tiny globules

B) watery regions

C) bacteria communities

D) little compartments

5. Commercial application of the research finding will be possible if salad dressing can be made resistant to bacteria 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

Now let's examine the correct answers to the questions and the errors that students may make in the test.

This passage talks about a study that aims to build up the resistance in cream to bacteria attack by altering the food's structure.

Question 1 concerns the main idea of the passage. To determine the main idea, the first step is to understand the important facts. Para. 1 says clearly "Some researchers think?a finding that could help rid some processed food of chemical preservatives." Brocklehurst was the lead researcher. Paragraphs 2, 3 and 4 tell why cream goes bad faster than butter. The last paragraph says "The researchers are already working with food companies keen to see if their products can be made resistant to bacteria attack through alterations of the food's structure." Certainly, the correct answer is A) it suggested a way to keep some foods fresh without preservatives. However, only 26 per cent of the test takers got the correct answer; 48 per cent of them were distracted by C) it revealed the secret of how bacteria multiply in cream and butter. They are wrong because the revelation of the secret is the finding, but not the significance of the research.

Question 2 tests the ability to recognize specific facts. Para. 3 quoted Brocklehurst: "This means that in cream, the bacteria are free to grow throughout the mixture." So the correct answer is B) (bacteria) multiply more easily in cream than in butter.

Question 3 is a specific question but needs a thorough understanding of the research finding. Para. 1 says, "Some researchers think they have the answer, and it comes down to the structure of the food?" Para. 3 describes the structures of cream and butter. "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." Then, the last paragraph says "The researchers are already working with food companies keen to see if their products can be made resistant to bacteria attack through alterations of the food's structure." Therefore, the correct answer to this question is D) altering its structure. However, 34 per cent of the test takers marked C) reducing its water content. Their assumption is based on common knowledge.

Question 4 concerns word guessing because the word "colonies" is not used in the sense known to students. Here the word refers to groups of bacteria. This question also tests the automatic recognition of substitute words. The previous sentence says "? the bacteria are locked away in ?" "Trapped in this way, individual colonies cannot spread ?" Of course, "colonies" refers to bacteria. So the correct answer is C).

Question 5 tests understanding of the last paragraph. The last sentence says, "? while keeping the salad dressing liquid." The correct answer is D) while retaining its liquid form. Half the test takers got the answer right. But 25 per cent marked C) while keeping its structure unchanged. They either confused the words "structure" and "form", or they didn't remember the word "retain". Their fault lies in their poor command of words.

Answers: A, B, D, C, D



THIS passage is from the CET-4 test of January, 2000. Read it and try to get the correct answers to the multiple-choice questions.



Amtrak (美国铁路客运公司) was experiencing a downswing in ridership (客运量) along the lines of 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, luxurious, and quite convenient compared to other forms of transportation 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.

1. 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 autos on the standard of convenience.

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

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

2. It can be inferred that the drop in Amtrak ridership was due to the fact that _____.

A) trains were not suitable for short distance 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 couldn't compete with planes in terms of convenience

3. To encourage people to travel by train, DDB Needham emphasized ________.

A) the freedom and convenience provided by trains

B) the practical aspects of trains

C) the adventurous aspects of train trips

D) the safety and cleanliness of train trips

4. The train ads were put among family TV programmes involving nature 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 were believed to be among the audiences

5. The Empire Builder enjoyed an increase in ridership because ____.

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

B) it provided an exciting travel experience

C) its passengers could enjoy the great western outdoors

D) it was widely advertised in newspapers in Chicago

Answers: C, B, C, D, A