1 . 阅读下面材料，在空白处填入适当的内容(1个单词)或括号内单词的正确形式。

Food from the air

Everyone has seen plants growing, but have you ever thought     1     they get their food? In the seventeenth century, a European scientist     2     (call) Van Helmot asked this question. Like most people, he thought that plants must get their food from soil. However, Van Helmot decided       3     (test) the theory with experiments.

First, he dried some soil, put it into a pot and weighed it. Next, he weighed a small tree, planted it in the pot and added rain water. Then, he watered it     4     (regular) with rain water.

After five years, he removed the tree from the pot and weighed it again. He found that the tree had gained     5     huge amount of weight. When he weighed the soil, however, it was almost exactly the same as it had been five years    6    . So Van Helmot drew the    7    (conclude) that the tree grew by drinking water. Though it turned out to be wrong, he showed the importance of the use of scientific evidence to support ideas.

We now know that plants and trees make their own food. Their leaves, when exposed     8     the air and sun, are like factories    9     can change the energy from the sun into chemical energy. During this process (过程), oxygen and sugar     10     (produce). The oxygen is released back into the air, and the sugar is used by the plant as food.

2 . Within the environmental movement, the question often arises whether global warming can be mitigated (缓解) by planting more vegetation. The idea is that the plants will consume carbon dioxide (CO2) that is causing the warming, while producing oxygen for us to breathe. This is acceptable on condition that global warming is indeed caused in some way by CO2 in the air.

However, actual scientific debate on the issue has shifted away from CO2 as the probable cause, especially after the findings that the temperatures changed 800 to 1000 years before carbon dioxide changed. In other words, CO2 levels are an indicator of temperature change, not a cause.

While there is nothing we can do to control the global climate, there is still a lot we can do to improve our local climates. Land use is the biggest decisive factor of local temperature and air quality. On clear days, the temperatures in big cities can be 5.6 degrees Centigrade higher than in the countryside around them. This is because the concrete (混凝土) of sidewalks and buildings and the asphalt (沥青) of roads take in sunlight and transform it into heat. Some get so hot, one could cook an egg on them! These vast surfaces of man﹣made stone also store lots of heat, which they radiate (散发) all night long. Just before sunrise, when the earth should be its coolest, roadways are still warm to touch.

If vegetation was blocking the Sun from the sidewalks and roads, the vegetation would absorb the sunlight, fueling the plants’ oxygen-making engines, and the rock would stay at surrounding temperatures. The easiest and most obvious choice is trees, particularly wide-reaching trees like the oak. Another possibility, especially outside the city centre, could be vine-covered trellises (棚架).Covering rooftops with grasses or other short vegetation reduces a building’s cooling cost as sharply as having trees or trellises that provide shade for windows does.

The reason why vegetation does not warm the air like rock does is that plants take water from the ground and evaporate (蒸发) it through their leaves. The Sun’s energy isn’t radiated as heat — it is used to change water into water vapor. The evaporative cooling works so well that the leaves stay 5.6 to 8.33 degrees Centigrade cooler than they would have been without water. While we can’t improve global climate, increased vegetation can help cool local climates.

1. Which of the following is True according to the passage?

A．With some effort, we can still affect global climate.

B．We can do a lot to improve the climate where we live.

C．Temperatures in big cities are usually lower than in the countryside.

D．The asphalt of roads throws back sunlight.

2. How does the author suggest we remedy the “heat islands” created by cities?

A．Planting full and wide-reaching trees.

B．Using vehicles that get better gas mileage.

C．Using energy-saving equipment.

D．Constructing dark-colored roofs on new buildings.

3. Which of the following is not implied by the article?

A．Darker colors absorb more sunlight and transform it into heat.

B．More thick materials store heat and give off it at night.

C．Human activity is changing global climate.

D．Vegetation is neither dark nor thick; thus, it reduces localized heating.

4. How can we use the information in this article?

A．Encourage the next generation to increase vegetation.

B．Promote rooftop gardening.

C．Remove vines and trellises from buildings.

D．A and B above.

5. In what ways do trees cool the surrounding air?
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3 . 阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

In today’s Science class, we learnt that human beings have five senses. Our teacher, Mr. Smith, asked us to find out    1    plants have senses, too. After some research, I found that,     2    (like) human, plants have only one or two senses.

Some plants can see the light from the sun, and grow towards    3    . What is    4    (amaze) is that plants    5    like eating small insects can sense the soft touches of the insects on their leaves. After they sense the insects, they move their    6    (leaf) all of a sudden to catch them. It has also been discovered that some plants can feel whether the animals around them want to hurt them or not. No one really knows how the plants can do this. The results of a recent experiment    7    (carry) out by some Italian and German scientists are amazing.

It    8    (observe) that when some plants sense dangerous insects, they give    9    a kind of smell for protection—the smell can attract other insects in the distance which can kill the dangerous ones.

I never    10    (know) plants were so clever.

5 . People often recommend planting trees to make cities greener, cleaner and healthier. But during heat waves, city trees can actually increase air pollution. Indeed, a new study finds that up to 60% of the ozone (臭氧) in a city’s air on hot days may have its origin in chemicals released by trees.

City trees offer a host of benefits. They provide cooling shade, absorb carbon dioxide, and also release oxygen into the air. But oxygen is far from the only gas that trees and certain other green plants release into the air. One of these chemicals is a hydrocarbon(碳氢化合物) that can react with burning pollutants, such as nitrogen oxides (氮氧化合物). The result is the formation of ozone which can cause airway diseases.

Galina Churkina works in Germany at Humboldt University of Berlin. She and her team wanted to explore how much chemicals released by trees could affect city air. To do this, the researchers turned to a computer. They asked it to model the likely reactions between plant chemicals and nitrogen oxides in air throughout the Berlin city area. To do that, the researchers fed in local weather data for two summers. One was 2006, when there was a heat wave. The other was 2014, when temperatures were mild.

An average daily high there in summer tends to be at roughly 25℃. On such a day, chemicals released by area greenery would likely have contributed to making about 6 to 20 percent of the ozone in the city’s air. But during a heat wave, when temperatures are more than 30℃ , tree-chemical emissions (发出物) are also high. As a result, they are now likely to be responsible for up to 60 percent of the ozone in air.

Churkina says her team was not surprised to see the contrary relationship between plants and pollution. The results, Churkina says, suggest city tree-planting programs should not ignore the role this greenery may play in bad summer air pollution. Adding more trees will improve quality of life only if those cities also undertake plans to sharply cut vehicle pollution (汽车污染).

1. What might people think of the new study finding?

A．Reasonable.

B．Intelligent.

C．Surprising.

D．Disappointing.

2. How does ozone come about according to the author?

A．It is released by trees and other green plants.

B．It directly comes from the burning of oxygen.

C．A part of nitrogen oxides results in ozone in the end.

D．It is from the chemical reaction between a hydrocarbon and burning pollutants.

3. What can we infer from the last two paragraphs?

A．The higher the temperature is, the more ozone forms.

B．There’re no emissions of chemicals in spring or autumn.

C．Churkina suggests the number of city trees be lessened.

D．Churkina was surprised at seeing the contrary finding first.

9 . Britain’s seed bank the only one in the world aiming to collect all of the planet’s wild plant species, has reached its goal of banking 10 percent by 2010.

The Millennium Seed Bank Project run by Kew Gardens — one of the oldest botanical gardens — will officially deposit the 24,200th species on Thursday, a pink, wild banana from China.

More than 50 countries are now on board with Kew’s giant task but vast places of the globe, including India and Brazil, still need to join in and donate seeds, director Paul Smith said.

The seed bank is one of the largest and most diverse in the world with more than 1.5 billion seeds. Its goal is to help protect the planet’s bio-diversity during a time of climate change.

The wild banana seed is under threat of extinction (灭绝) in southwest China from agricultural development. It is a vital food source for Asia elephants and important for growing bananas for human consumption.

The seeds are stored at minus 20 degrees centigrade. So they can last for thousands of years, the seeds await the day that scientists hope never comes — when the species no longer exist in the wild.

It is a race against time, Smith said, because in the last decade alone, 20 plants held in the bank have already been wiped out in the wild. He estimates that between a third and a quarter will become extinct this century.

“It is urgent and it is happening now. An area, the size of England, is cleared of primary vegetation (植被) every year.” Smith said.

Because most of the world’s food and medicines come from nature, protecting wild plant species is quite important, scientists say. There are already many other seed banks safeguarding food crops, which only account for 0.6 percent of plant diversity.

For Kew’s next goal — to collect a quarter of wild varieties by 2020 — the botanists need 10 million pounds a year, or a further 100 million pounds on top of the 40 million they have already been granted.

1. What’s the final purpose of the Britain’s seed bank?

A．To collect enough money for the project.

B．To safeguard food crops.

C．To help scientists study wild plants.

D．To protect wild plants from extinction.

2. The wild banana seed in China is in danger because of ________.

A．the climate change in this area	B．the expanding of farming work
C．the large number of Asian elephants	D．human’s large consumption

3. We can learn from the passage that ________.

A．the seeds in the bank can be used now and then all over the world

B．there is only one seed bank in the world at present

C．India and Brazil haven’t joined in the Seed Bank Project at present

D．the wild plants in places like India and China will never die out

4. What does the underlined word “It” in paragraph 7 refer to?

A．The extinction of plant species.	B．Kew Gardens’ next goal.
C．The Millennium Seed Bank Project.	D．Britain’s seed bank.

5. Which of the following information isn’t mentioned in the passage?

A．The global partnership of collecting wild plant species.

B．The temperature condition of the conservative wild plant species.

C．Scientists’ concern on the extinct wild plant species.

D．The government’s financial support for the seed bank project.