By the mid-nineteenth century, the “icebox” had entered the American language, but ice was still only beginning to affect the diet of ordinary citizens in the United States. The ice trade grew with the growth of cities. Ice was used in hotels, taverns, and hospitals, and by some forward-looking city dealers in fresh meat, fresh fish, and butter. After the Civil War (1861-1865), as ice was used to refrigerate freight cars, it also came into household use. Even before 1880, half the ice sold in New York, Philadelphia, and Baltimore, and one-third of that sold in Boston and Chicago, went to families of their own use. This had become possible because a new household convenience, the icebox, a precursors of modern refrigerator, had been invented.
Making an efficient icebox was not as easy as we might now suppose. In the early nineteenth century, the knowledge of physics of heat, which was essential to a science of refrigeration, was rudimentary. The commonsense notion that the best icebox was one that prevented the ice from melting was of course mistaken, for it was melting of the ice that performed the cooling. Nevertheless, early efforts to economize ice included wrapping the ice in blankets, which kept the ice from doing its job. Not until near the end of the nineteenth century did inventors achieve the delicate balance of insulation and circulation needed for an efficient icebox.
But as early as 1803, an ingenious Maryland farmer, Thomas Moore, had been on the right track. He owned a farm about twenty miles outside the city of Washington, for which the village of Georgetown was the market center. When he used an icebox of his own design to transport his butter to market, he found that customers would pass up the rapidly melting stuff in the tubs of his competitors to pay a premium(奖金) price for his butter, still fresh and hard in neat, one-pound bricks. One advantage of his icebox, Moore explained, was that farmers would no longer have to travel to market at night in order to keep their produce cool.
【小题1】What does the passage mainly discuss?

E
Although we already know a great deal about flu, and although the World Health Organization is constantly collecting detailed information from its chain of flu reference laboratories throughout the world, it is extremely difficult for epidemiologists, who study infectious diseases, to predict when and where the next flu epidemic will occur, and how serious it will be. 
There are three kinds of flu virus, known as A, B and C. Flu C virus is relatively stable and causes mild infections that do not spread far through the population. The A and B types are unstable, and are responsible for the epidemics that cause frequent concern. Following any virus attack, the human body builds up antibodies （抗体） which can be changed into immunity to that type of virus but a virus with the ability to change its character is able to bypass this protection. Variability（可变性） is less developed in the flu B virus, which affects only human beings. Flu B virus may cause a widespread epidemic but will have little effect if introduced into the same community soon afterwards, since nearly everyone will have built up antibodies and will be immune. The flu A virus, which affects animals also, is extremely unstable and is responsible for some of the worst outbreaks of the disease, such as the world epidemic, of 1918 and 1919, when about half the world’s population were infected and about twenty million people died, some from pneumonia caused by the virus itself and some from secondary complication caused by bacteria. Accurate prediction is difficult because of the complication of the factors. A particular virus may be related to one to which some of the population have partial involved immunity. The extent to which it will spread will depend on factors such as its own strength, or virulence （病毒性）, the ease with which it can be transmitted and the strength of the opposition it encounters （遇到）. Scientists, however, have a reliable general picture of the world situation. 
72. Which of the following is the most appropriate title for the passage? 
A. Symptoms of Flu                                                       B. Man VS Flu Virus 
C. WHO: The Major Organization against Flu Virus       D. Variability of Flu Virus 
73. What does the author say about the flu B virus? 
A. B Virus is relatively stable and causes mild infections that do not spread far through the population. 
B. B Virus is unstable, and is responsible for the epidemics that cause frequent concern. 
C. B virus is extremely unstable and is responsible for some of the worst outbreaks of the disease. 
D. B virus has a very developed variability, and it affects only human beings. 
74. Which of the following is NOT mentioned as a factor contributing to the extent to which a virus spreads?
A. The strength of the virus.               B.The ease with which the virus can be transmitted.
C. The strength of the opposition. D.The immunity the virus can bring about.
75. This article is quite probably ________.
A. a piece of news                                    B. a special science report
C. an introduction to a disease             D. a scientific fiction 

About twenty of us had been fortunate enough to receive invitations to a film-studio(影棚)to take part in a crowd-scene. Although our "act" would last only for a short time, we could see quite a number of interesting things.
We all stood at the far end of the studio as workmen prepared the scene, setting up trees at the edge of a winding path. Very soon, bright lights were turned on and the big movie-camera was
wheeled into position. The director shouted something to the camera operator and then went to speak to the two famous actors nearby. Since it was hot in the studio, it came as a surprise to us to see one of the actors put on a heavy overcoat and start walking along the path. A big fan began blowing tiny white feathers down on him, and soon the trees were covered in "snow". Two more fans were turned on, and a "strong wind" blew through the trees. The picture looked so real that it made us feel cold.
The next scene was a complete contrast (对比). The way it was filmed was quite unusual. Pictures in front taken on an island in the Pacific were shown on a glass screen (幕). An actor and actress stood of the scene so that they looked as if they were at the water’s edge on an island. By a simple trick like this, palm trees, sandy beaches, and blue, clear skies had been brought into the studio!
Since it was our turn next, we were left wondering what scene would be prepared for us. For a full three minutes in our lives we would be experiencing the excitement of being film "stars"!
【小题1】Who is the author?

About twenty of us had been fortunate enough to receive invitations to a film-studio(影棚)to take part in a crowd-scene. Although our "act" would last only for a short time, we could see quite a number of interesting things.
We all stood at the far end of the studio as workmen prepared the scene, setting up trees at the edge of a winding path. Very soon, bright lights were turned on and the big movie-camera was
wheeled into position. The director shouted something to the camera operator and then went to speak to the two famous actors nearby. Since it was hot in the studio, it came as a surprise to us to see one of the actors put on a heavy overcoat and start walking along the path. A big fan began blowing tiny white feathers down on him, and soon the trees were covered in "snow". Two more fans were turned on, and a "strong wind" blew through the trees. The picture looked so real that it made us feel cold.
The next scene was a complete contrast (对比). The way it was filmed was quite unusual. Pictures in front taken on an island in the Pacific were shown on a glass screen (幕). An actor and actress stood of the scene so that they looked as if they were at the water’s edge on an island. By a simple trick like this, palm trees, sandy beaches, and blue, clear skies had been brought into the studio!
Since it was our turn next, we were left wondering what scene would be prepared for us. For a full three minutes in our lives we would be experiencing the excitement of being film "stars"!
【小题1】Who is the author?

Five years ago, David Smith wore an expensive suit to work every day. “I was a clothes addict(迷),” he jokes. “I used to carry a fresh suit to work with me so I could change if my clothes got wrinkled(皱的).” Today David wears casual clothes — khaki pants and a sports shirt — to the office. He hardly ever wears a necktie. “I’m working harder than ever,” David says, “and I need to feel comfortable.”
More and more companies are allowing their office workers to wear casual clothes to work. In the United States, the changes from formal to casual office wear have been slow. In the early 1990s, many companies allowed their workers to wear casual clothes on Friday (but only on Friday).This became known as “dress-down Friday” or “casual Friday”. “What started out as an extra one-day-a-week benefit for workers has really become an everyday thing,” said business adviser Maisly Jones.
Why have so many companies started allowing their workers to wear casual clothes? One reason is that it’s easier for a company to attract new workers if it has a casual dress code. “A lot of young people don’t want to dress up for work,” says the owner of a software company, “so it’s hard to hire people if you have a conservative dress code.” Another reason is that people seem happier and more productive when they are wearing comfortable clothes. In a study made by Levi Strauss and Company, 85 percent of employers said that casual dress has a side effect on work. Supporters of casual office wear also say that a casual dress code helps them save money. “Suits are expensive, if you have to wear one every day,” one person said. “For the same amount of money, you can buy a lot more casual clothes.”
【小题1】David Smith refers to himself as having been “a clothes addict” because ______________.