1 . Eating too much fatty food, exercising too little and smoking can raise your future risk of heart disease. But there is another factor that can cause your heart problems more immediately：the air you breathe.

Previous studies have linked high exposure (暴露) to environmental pollution to an increased risk of heart problems，but two analyses now show that poor air quality can lead to heart attack or stroke (中风) within as little as a few hours after exposure. In one review of the research, scientists found that people exposed to high levels of pollutants (污染物) were up to 5% more likely to suffer a heart attack within days of exposure than those with lower exposure. A separate study of stroke patients showed that even air that the U. S. Environmental Protection Agency (EPA)considers to be of “moderate” (良好) quality and relatively safe for our health can raise the risk of stroke as much as 34% within 12 to 14 hours of exposure.

The authors of both studies stress that these risks are relatively small for healthy people and certainly modest compared with other risk factors such as smoking and high blood pressure. However, it is important to be aware of these dangers because everyone is exposed to air pollution regardless of lifestyle choices. So stricter regulation by the EPA of pollutants may not only improve environmental air quality but could also become necessary to protect public health.

1. The text mainly discusses the relationship between ________.

A．heart problems and air quality

B．heart problems and exercising

C．heart problems and smoking

D．heart problems and fatty food

2. The underlined word “modest” in Paragraph 3 most probably means ________.

A．relatively high	B．extremely low
C．relatively low	D．extremely high

3. What can we learn from the text?

A．Eating fatty food has immediate effects on your heart.

B．The EPA conducted many studies on air quality.

C．Moderate air quality is more harmful than smoking.

D．Stricter regulations on pollutants should be made.

4. The author's purpose of writing the text is most likely to ________.

A．inform	B．persuade
C．describe	D．entertain

2 . Far from the land of Antarctica, a huge shelf of ice meets the ocean. At the underside of the shelf there lives a small fish, the Antarctic cod.

For forty years scientists have been curious about that fish. How does it live where most fish would freeze to death? It must have some secret. The Antarctic is not a comfortable place to work and research has been slow. Now it seems we have an answer.

Research was begun by cutting holes in the ice and catching the fish. Scientists studied the fish’s blood and measured its freezing point.

The fish were taken from seawater that had a temperature of -1.88℃ and many tiny pieces of ice floating in it. The blood of the fish did not begin to freeze until its temperature was lowered to -2.05℃. That small difference is enough for the fish to live at the freezing temperature of the ice-salt mixture.

The scientists’ next research job was clear: Find out what in the fish’s blood kept it from freezing. Their search led to some really strange thing made up of a protein never before seen in the blood of a fish. When it was removed, the blood froze at seawater temperature. When it was put back, the blood again had its antifreeze quality and a lowered freezing point.

Study showed that it is an unusual kind of protein. It has many small sugar molecules held in special positions within each big protein molecule. Because of its sugar content, it is called a glycoprotein. So it has come to be called the antifreeze fish glycoprotein. Or AFGP.

1. What is the text mainly about?

A．The terrible conditions in the Antarctic.

B．A special fish living in freezing waters.

C．The ice shelf around Antarctica.

D．Protection of the Antarctic cod.

2. Why can the Antarctic cod live at the freezing temperature?

A．The seawater has a temperature of -1.88℃.

B．It loves to live in the ice-salt mixture.

C．A special protein keeps it from freezing.

D．Its blood has a temperature lower than -2.05℃.

3. What does the underlined word “it” in Paragraph 5 refer to?

A．A type of ice-salt mixture.	B．A newly found protein.
C．Fish blood.	D．Sugar molecule.

4. What does “glyco-” in the underlined word “glycoprotein” in the last paragraph mean?

A．sugar	B．ice
C．blood	D．molecule

3 . Before I studied psychology, I used to think that people would laugh when funny things occurred. While I was right about that, I discovered there are lots of other psychological factors that make people laugh other than the funny part of a joke. When someone laughs at a joke, there will usually be more than one reason that makes him laugh—and the more reasons there are, the more powerful the joke will be.

I was attending a stand­up comedy show in Egypt, and when the man started to make fun of pedestrians crossing streets, everyone laughed their heads off. The main reason why those people strongly laughed was that almost all of them felt angry towards pedestrians who crossed streets carelessly. The joke wasn't only funny, but it also made the audience feel that they were right about being angry at those pedestrians. That is, people were laughing both because of the funny joke and because of the happiness experienced as a result of the psychological support they got.

The better a joke makes a person feel, and the more it includes other psychological factors, the more the person will like it. For example, if you envy one of your friends, and someone tells a joke that is funny and, at the same time, makes your friend seem stupid, then you will probably laugh at it louder than if you weren't jealous of him.

In short, we don't laugh only when we hear something funny; we also laugh when we experience some kind of happiness that results from the other psychological factors involved in the joke. I strongly discourage you from making fun of anyone or belittling someone to make someone else laugh. All I want to explain is that if your joke supports a person's emotions, he will certainly like it a lot.

1. What did the author find out after studying psychology?

A．Only good jokes make people laugh.

B．Many factors lead to people's laughing.

C．Funny things can make people laugh.

D．Laughter can make people healthy.

2. Why did the audience laugh loud at the pedestrians?

A．They played a trick on the pedestrians.

B．The pedestrians behaved in a funny way.

C．They could feel the pedestrians' happiness.

D．Their emotion was approved of by the show.

3. What does the underlined word “belittling” probably mean?

A．Annoy.	B．Blame.
C．Look down on.	D．Make up to.

4. Which of the following best shows the structure of the passage?

A．	B．
C．	D．