2 . Most scientists are now certain that global warming is taking place. Gases such as carbon dioxide are creating a warm blanket around the earth. This blanket is trapping heat in the atmosphere, and so raising the temperature of the earth.

In Europe, eight of the last ten years have seen record high temperatures. On the other hand, the countries around the Mediterranean Sea are receiving even less rain than before. In Sub- Saharan Africa the crops are drying out in the fields and people are dying of starvation. In 1999, the southern United States was struck by a serious of destructive(毁灭性的) hurricanes. Scientists expect such trends to continue, and to worsen, if global warming cannot be stopped.

In addition to worrying about rising global temperatures and extreme weather conditions, scientists are closely monitoring sea levels around the world. They are slowly rising, as the northern and southern polar ice caps start to melt. This will have serious consequences for low-lying countries near the sea. Already parts of these places are disappearing under the rising sea water.

According to a new research, one contradictory feature(特征) of global warming is that it will probably lead to a period of much colder weather. Scientists base their theory on what happened the last time the world warmed up, 8,300 years ago. They have discovered that when the ice melted from the northern polar ice cap it became trapped in a lake in northern Canada. As more ice melted, this lake suddenly burst open, pouring millions of tons of freezing fresh water into the North Atlantic. This flood of water prevented the normal flow of water in the Atlantic, which takes warm water from the tropics(热带地区) north to Europe. When this flow of warm water was cut off, temperatures in Europe dropped by between three and eight degrees over the next 200 years. ''That's the concern here,'' says Richard Alley, an American climate expert. ''The climate hasn't varied much in 8, 000 years. But big changes could come back!''

1. What is the overall effect of global warming on Europe?

A．A warmer climate.	B．A decline in rainfall.
C．An increase of hurricanes.	D．A decrease of crop production.

2. What is Paragraph 3 mainly about?

A．The rising sea level.	B．The melting of icebergs.
C．The increase in disasters.	D．The cause of global warming.

3. How does the author describe the climate change in Europe 8 ,300 years ago?

A．By offering statistics.	B．By giving an example.
C．By making comparisons.	D．By analyzing the process.

4. What can we infer from Richard Alley' s words?

A．Global climate change will bring more disasters.

B．Global warming will likely produce a colder climate.

C．Global warming will continue for the next two centuries.

D．Global climate will remain unchangeable in the next 8,000 years.

3 . By the end of the century, if not sooner, the world’s oceans will be bluer and greener thanks to a warming climate, according to a new study.

At the heart of the phenomenon lie tiny marine microorganisms(海洋微生物) called phytoplankton. Because of the way light reflects off the organisms, these phytoplankton create colourful patterns at the ocean surface. Ocean colour varies from green to blue, depending on the type and concentration of phytoplankton. Climate change will fuel the growth of phytoplankton in some areas, while reducing it in other spots, leading to changes in the ocean’s appearance.

Phytoplankton live at the ocean surface, where they pull carbon dioxide(二氧化碳) into the ocean while giving off oxygen. When these organisms die, they bury carbon in the deep ocean, an important process that helps to regulate the global climate. But phytoplankton are vulnerable to the ocean’s warming trend. Warming changes key characteristics of the ocean and can affect phytoplankton growth, since they need not only sunlight and carbon dioxide to grow, but also nutrients.

Stephanie Dutkiewicz, a scientist in MIT’s Center for Global Change Science, built a climate model that projects changes to the oceans throughout the century. In a world that warms up by 3℃, it found that multiple changes to the colour of the oceans would occur. The model projects that currently blue areas with little phytoplankton could become even bluer. But in some waters, such as those of the Arctic, a warming will make conditions riper for phytoplankton, and these areas will turn greener. “Not only are the quantities of phytoplankton in the ocean changing. ” she said, “but the type of phytoplankton is changing.”

And why does that matter? Phytoplankton are the base of the food web. If certain kinds begin to disappear from the ocean, Dutkiewicz said, “it will change the type of fish that will be able to survive.” Those kinds of changes could affect the food chain.

Whatever colour changes the ocean experiences in the coming decades will probably be too gradual and unnoticeable, but they could mean significant changes. “It’ll be a while before we can statistically show that the changes are happening because of climate change,” Dutkiewicz said, “but the change in the colour of the ocean will be one of the early warning signals that we really have changed our planet.”

1. What are the first two paragraphs mainly about?

A．The various patterns at the ocean surface.

B．The cause of the changes in ocean colour.

C．The way light reflects off marine organisms.

D．The efforts to fuel the growth of phytoplankton.

2. What does the underlined word “vulnerable” in Paragraph 3 probably mean?

A．Sensitive.

B．Beneficial.

C．Significant.

D．Unnoticeable.

3. What can we learn from the passage?

A．Phytoplankton play a declining role in the marine ecosystem.

B．Dutkiewicz’s model aims to project phytoplankton changes.

C．Phytoplankton have been used to control global climate.

D．Oceans with more phytoplankton may appear greener.

4. What is the main purpose of the passage?

A．To assess the consequences of ocean colour changes.

B．To analyse the composition of the ocean food chain.

C．To explain the effects of climate change on oceans.

D．To introduce a new method to study phytoplankton.

4 . One of the questions surrounding climate change is how it might affect the food supply for a growing global population. A new study suggests that researchers have been overlooking how two key human responses to climate—how much land people choose to farm, and the number of crops they plant—will affect food production in the future. The new study focused on the Brazilian state of Mato Grosso, an emerging（新兴的）global breadbasket（产粮地区）that as of 2013 supplied 10 percent of the world’s soybeans. The researchers used variations in temperature and precipitation（降水）across the state over an eight-year period to estimate the sensitivity of the region’s agricultural production to climate change. Those historical comparisons can help in making predictions about the sensitivity of agriculture to future climate change.

The study found that, if the patterns from 2002 to 2008 hold in the future, an increase in average temperature in Mato Grosso of just 1 degree will lead to a 9 to 13 percent reduction in overall production of soy and corn. “This is worrisome given that the temperature in the study region is predicted to rise by 2 degrees by 2050,” said Avery Cohn, who led the study.

Most studies of this kind look only at the extent to which climate shocks affect crop output. But researchers can miss critical dynamics（动力）that can affect overall output, says Leah VanWey, one of the study’s senior authors. “If you look at output alone, you’re not looking at all of the information because there are economic and social changes going on as well,” said VanWey.

If output decreases, farmers may put less land area into production because it’s not profitable. Farmers may also vary the number of crops they plant in a growing season. Double cropping is common in Mato Grosso. But if the weather is bad, farmers may change their decision to plant a second crop.

1. The value of the new study lies in _________.

A．increasing the number of crops people plant

B．focusing on an emerging global breadbasket

C．making predictions about human responses to climate change

D．controlling people’s choice of their farming area and crop numbers

2. According to Avery Cohn, by 2050, the overall production of soy and corn will _________.

A．remain almost unchanged	B．decrease by more than 9%
C．increase by from 9% to 13%	D．decrease by more than 18%

3. What can we know about the similar studies mentioned in paragraph 3?

A．They can’t provide exact information to farmers.

B．They don’t take into consideration some key factors.

C．Their discouraging results largely affect overall crop output.

D．They pay too much attention to economic and social changes.

4. What is the last paragraph mainly about?

A．Farmers’ possible reactions to climate shocks.

B．Possible climate change in Mato Grosso.

C．The benefits of double cropping in Mato Grosso.

D．Farmers’ decision on planting crops in the future.

5 . Climate change will increase US wildfires,and the smoky air will cause terrible problems in areas far beyond those burned,reports an environmental group Thursday.

Two-thirds of Americans,or nearly 212 million,lived in states suffering from wildfire smoke three years ago,according to the report by the Natural Resources Defense Council(NRDC).These areas,which had smoke for at least a week,were nearly 50 times greater than those burned directly by fire.

“It affects a much wide area of the United States than people have realized.” says author Kim Knowlton,a Columbia University health professor,adding the smoke can move up to hundreds of miles.She says the smoke contains air pollution and can cause several kinds of diseases.

Texas was hit hardest in 2011,when smoke stayed for at least a week in areas that are home to 25 million people,according to NRDC’s report.Illinois,which recorded no wildfires within its borders, came second with nearly 12 million people affected by smoke that moved in from elsewhere.The other eight states with the most people in touch with smoky air were,in descending   order: Florida,Missouri,Georgia,Louisiana,Michigan,Alabama,Oklahoma and Iowa.

Nearly two dozen states had no wildfires within their borders in 2011,but eight of them still had at least one week of smoky air: Illinois,Missouri，Iowa,Kansas,Nebraska,Indiana,Wisconsin and Ohio.

Only 18 states and the District of Columbia had no people in touch with at least a week of smoke that year,although five of them—Alaska,California,Hawaii,Nevada and Utah—had a large area burned by wildfires.

The problem will only get worse.Knowlton says.Scientific research shows climate is causing higher temperatures and health problems.

1. We can learn from the first two paragraphs that_______.

A．climate change killed many Americans

B．there are fewer states burned by wildfires

C．every state had wildfire smoke for at least a week

D．most Americans suffered from wildfire smoke 3 year ago

2. Which of the following states had wildfires within its borders in 2011?

A．Iowa.	B．Kansas.
C．Ohio.	D．California.

3. The underlined word “descending” in the fourth paragraph probably means _______.

A．going down	B．coming true
C．looking practical	D．turning back

4. What is the text mainly about?

A．Climate change causes more wildfires.

B．Wildfire smoke becomes a serious health problem.

C．More wildfires cause climate changes.

D．Air pollution becomes a terrible problem.