1 . Scientists have discovered how plants manage to live alongside each other in places that are dark and shady. Plants in the deep darkness of a thick forest, where natural supplies are not very great in amount, won’t attempt to top their neighbors in growth as those in moderate (中度的) shade do. In deep shade conditions, it would be a waste of energy and harmful to survival because green shoots would never be able to top their larger neighbors in growth.

So how do plants prevent such growth in deep shade conditions? The secret lies in the clocks insides them, say scientists from the John Ines Centre and the University of Bristol.

They have discovered that when plants notice deep shade, this changes the expression of genes parts of the circadian clock (昼夜节律时钟) — the inner daily timer found in plants and other things. These clock parts perform an additional role in preventing plants from lengthening and overtopping neighbors.

The work identifies a previously unknown role of the circadian clock in controlling plant development and the findings may have possible effects on both natural plant populations and crops. Professor Antony Dodd of the John Innes Centre said, “The biological clock of plants plays a big part in their development and fitness. This work casts new light on a new role of the circadian clock in adapting plants to competition with other plants in their environments.” “It also gives us new insights into how plants adapt to very deep shade, where resources are very limited,” said Professor Kerry Franklin at the University of Bristol.

This work provides evidence for the firmness of the circadian clock in stressful environments, and information that may be useful in developing new generations of crops in a challenging climate.

1. What do plants normally do in moderate shade?

A．Struggle to preserve energy.	B．Compete for limited resources.
C．Try to outgrow their neighbors.	D．Depend on each other to survive.

2. How does the circadian clock affect plants?

A．By changing their gene expression.	B．By making them realize light change.
C．By helping them adapt to the darkness.	D．By controlling their growth in deep shade.

3. Why does the author write the text?

A．To share a new discovery about plants.	B．To introduce the role of the circadian clock.
C．To explain plants secret of living in forests.	D．To compare plants living in certain condition.

4. What is the best title for the text?

A．How plants face a challenging climate

B．Why plants respond to different shade levels

C．Why the circadian clock is vital to plants' growth

D．How plants become good neighbors in times of stress

2 . A wildfire kills most things in its path, but despite the flames and intense temperatures, rarely is everything reduced to ashes -and that plays a key role in a forest's regeneration. Just one year after the fire, the survivors dominate the forest, and grasses replace the burnt ground. Wildflowers are abundant bushes and small trees have started to grow, and Jack Pine returned. So, it's an amazing ecological system of creating new forest life when it appears that all is lost, one that has evolved throughout the ages, where fire has always played a vital role.

What does the underlined word "one" in the last paragraph refer to?

A．A fire.

B．A life

C．A time.

D．A system

3 . Early last summer, I bought some yam（山药）roots for food but days later, a tuber （块茎）left was sprouting（发芽）. Thinking it was a waste of money to throw it away, I _____ the tuber into a flower pot hoping that it might take root and ______ something that could be put on the dinner table.

In the following months, I ____ the tuber regularly. Thankfully, the _____ yam grew well. Soon it was autumn, and I decided to ______ .

I pulled out the leaves of the yam and began to dig with my fingers carefully for I knew the yam could ______easily. Suddenly my fingers __ the yam root. When almost no __ was left, I tried to pull the root but failed.

In ______   , I turned the pot over. Half of the yam root had grown through one of the three holes ______

The whole tuber, _____ two parts, one in and one out of the pot, was in the _____ of a handwritten L. Unlike ordinary yam roots, the part outside the pot was not round—it was _____ , looking like a hand of an old farmer who works hard to make a ______ . The very end of the part outside the pot was _____ . Obviously, the skin must have been rubbed off during its __ with the heavy pot. The very tip of the unusual part seemed to be bleeding.

The sight filled me with ______ . Then and there my opinion of the plant _____ . I came to understand that the tuber, though ______ wounded, had struggled hard. Such was a yam, an ordinary-looking plant with ________characteristics.

1.

A．cooked

B．ruined

C．buried

D．cut

2.

A．remove

B．produce

C．replace

D．protect

3.

A．bought

B．threw

C．watered

D．ate

4.

A．abandoned

B．forgotten

C．injured

D．potted

5.

A．perform

B．attempt

C．harvest

D．withdraw

6.

A．stand

B．grow

C．fall

D．break

7.

A．touched

B．pulled

C．crashed

D．killed

8.

A．earth

B．root

C．air

D．plant

9.

A．excitement

B．shame

C．puzzlement

D．terror

10.

A．in the sky

B．on the top

C．in the bottom

D．under the ground

11.

A．picking out

B．consisting of

C．giving away

D．taking down

12.

A．color

B．form

C．voice

D．size

13.

A．flat

B．long

C．rough

D．weak

14.

A．choice

B．contribution

C．wish

D．living

15.

A．skinless

B．endless

C．useless

D．stainless

16.

A．negotiation

B．struggle

C．cooperation

D．relationship

17.

A．victory

B．regret

C．envy

D．respect

18.

A．strengthened

B．changed

C．disappeared

D．remained

19.

A．barely

B．temporarily

C．purposefully

D．seriously

20.

A．tough

B．steady

C．common

D．gentle

4 . The Greenwood fire took its name from the nearby lake where lightning struck on Aug.15, causing a wildfire that burned for weeks. Fueled by drought and wind, its persistence dominated headlines for much of late summer and early fall in Minnesota. When the last flames were finally put out, the northern Minnesota fire had consumed nearly 27,000 acres, countless firefighting resources, and at its worst, the lives that some had built around nearby McDougal Lake. Vast areas of forest were left burned-out, with the black and bare remains of what were once massive pines.

But, despite the destruction left behind, Mother Nature is set to a comeback. When organic matter is burned from the forest floor, seeds dropped by plants and trees begin to take hold, with the sprouting species emerging first. The trees above have died, which sends a chemical signal to the root system that is actually more expansive than just under that tree, and that chemical response encourages those root systems to re-grow. Ten years ago, a fire ripped through 93,000 acres of Minnesota forest in and around the BWCA. Today, that burnt area's rebirth is well underway.

"Here in the Pagami Creek wildfire scar, we have Jack Pine, Red Pine, Black Spruce, Aspen and paper birch-those are our main species, those are the ones that are growing quickly. It's 10 years on, and these trees are 10 to 15 feet tall in many areas," said Kyle Stover from the U.S. Forest Service.

A wildfire kills most things in its path, but despite the flames and intense temperatures, rarely is everything reduced to ashes -and that plays a key role in a forest's regeneration. Just one year after the fire, the survivors dominate the forest, and grasses replace the burnt ground. Wildflowers are abundant bushes and small trees have started to grow, and Jack Pine returned. So, it's an amazing ecological system of creating new forest life when it appears that all is lost, one that has evolved throughout the ages, where fire has always played a vital role.

1. What can we learn about the Greenwood fire?

A．It was a natural occurrence	B．It was caused by drought.
C．it gained half-year fame.	D．It took many people's lives.

2. What happens to the burnt area after the fire?

A．Seeding growth is held up.	B．Burnt organic matter hardly functions.
C．Root systems spread further and wider	D．Chemicals in the soil are in greater demand.

3. What can we say about the trees and plants in Minnesota?

A．They are flammable	B．They are fire-resistant
C．They are fire-adapted.	D．They are overgrown.

4. What does the underlined word "one" in the last paragraph refer to?

A．A fire.

B．A life

C．A time.

D．A system

5 . Now a group of Italians have created the world’s first underwater garden for terrestrial plants. Called Nemo’s Garden, the project was launched by the Ocean Reef Group as a means to experiment with food supply diversity, should climatic changes make parts of Italy too dry to farm. The large self-sustaining, totally-contained biospheres would in theory be scalable, and perhaps in the future might look like the underwater city from Star Wars: The Phantom Menace.

The challenge existing in growing plants underwater, given that they are normally at home in soil, was but one obstacle Nemo has had to overcome. The six air-filled greenhouses suffered major storm damage in October 2019, and before they could be fully repaired, COVID-19(新冠病毒) had all the researchers sheltering in place.

Yet the team never gave up hope, as Euronews reports, and the months of abandonment did not harm the facility in any way. June 6th saw the garden fully-operational again, including their live stream where one can watch the plants grow. The biospheres(生物圏), which sit eight meters under the surface off the coast of Noli in Liguria, use solar energy for their minimal electrical needs, and evaporated seawater condenses(凝结) on the glass of the ceiling which waters the plants. A diver swims under and up into the air pocket of the pod to harvest what’s ready to eat.

The project website says that increased pressure like that found under the ocean is actually beneficial to the speed at which plants can come up, though they admit very little research has been published on the topic—after all, not so many people are currently trying to grow strawberries it underwater.

The conditions create a really intense flavor in the vegetables, and also allow the plants’ environment to be completely controlled, with nothing impacting their life dial the growers don’t want. For now Nemo’s Garden is essentially a research lab, but if tie idea were expanded, it’s expected to be able to keep food security for the peninsula, and the world.

1. Why was Star Wars: The Phantom, Menace mentioned?

A．To stress it is known to the world.

B．To prove it has becomes u popular destination.

C．To illustrate it is the first existing underwater city.

D．To explain Nemo’s Garden has similarities with the underwater city.

2. What might be the difficulty in growing underwater plants according to Paragraph 2?

A．COVID-19.	B．Broken greenhouses.
C．Frequent storms   .	D．Shortage of soil.

3. Which word can best describe the group of Italians taking up Nemo’s Garden?

A．Strong-willed.	B．Self-confident.
C．Open-minded.	D．Well-paid.

4. What is the effect of increased stress on plants?

A．It helps them sell well.	B．It contributes to good taste.
C．It promotes their growth.	D．It increases growing period.

6 . Directions: Write the summary of the passage with no more than 60 words and the original sentences in the passage are not allowed to use.

When people think of plants, they usually think of gardens, parks, or even jungles. One place that does not usually come to mind is the desert. However, some deserts contain many plants that are able to grow and survive under difficult conditions.

Deserts can reach temperatures of 50 degrees or more in the daytime and can also drop below 0 degrees at night. This is a huge temperature difference under which desert plants have to live. Besides the high and low temperatures, all deserts receive very little water in the form of rain; sometimes it doesn’t rain for months. So, how do desert plants get water when there is no rain?

There are three main ways plants survive in the desert. First, some desert plants grow without leaves. Others have developed special ways of storing whatever water they can find, such as growing a waxy leaf covering that helps keep water inside the leaf. These plants can survive for weeks or months on the water collected from just one rainfall.

A second way desert plants survive even in the most difficult conditions is by growing very long roots. These roots spread out and search for any water they can find. Once they find water, the roots suck up as much as they can and then hold it, only allowing the plant above the ground to have small amounts at a time.

The third way plants survive in the desert is by “sleeping”. Some plants can turn off almost all their processes and just remain inactive, almost as if dead, while they wait for rain. When the rain does come, they quickly drink up every drop they possibly can and burst back into activity.

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7 . 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。

Yuan Longping, Father of Hybrid Rice,     1     passed away on Saturday at 91, will be long remembered as one of the most honorable leaders, the World Food Prize Foundation said.

Yuan was a co-winner of the 2004 World Food Prize, the top international honor recognizing the deeds of     2     (individual) who have advanced human development by     3     (improve) the quality, quantity and availability of food in the world. Yuan shared it with Monty Jones, an African rice breeder.

Yuan’s pioneering research has     4     (complete) helped transform China from food shortage to food security within three decades, according to an earlier statement     5    (release) by the WFP.

Barbara Stinson, president of the WFP Foundation, said Yuan was credited not only for hybrid rice, but also for the ability     6    (change) land out of rice production and into other kinds of food production, including fish ponds, other fruits and vegetables, increasing the nutritional content of food in China, and contributing     7     the reduction of hunger and poverty as well.

Yuan started hybrid rice research in 1964 and     8    (succeed) in developing the world’s first high-yield hybrid rice strain in 1973. So far, its annual growth area     9    (reach) 8 million hectares (公顷)in countries including India, Bangladesh, Vietnam) Brazil and the US.

“He’s made such     10     powerful contribution. Professor Yuan will be long remembered. ” Stinson told China Daily.

8 . 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。

As the world    1    （large）cotton consumer and the second largest producer of cotton, China has a long history of cotton cultivation. It is worth    2    （mention）that Xinjiang cotton is highly regarded because of its high yield and high quality.

    3    （locate）in the inland of Eurasia（欧亚大陆）, Xinjiang has a typical mild continental climate. Drought, little rain, sufficient heat, big temperature    4    （different）between day and night and long day make a good growth environment for cotton.

Though Xinjiang has little rainfall, it has a large number of snow-capped mountains, from which meltwater gives cotton abundant water resource. Meanwhile,    5    contrast to the instable rainfall in the monsoon（季风）regions, mountain snowmelt has the characteristics of stable water transportation,    6    is very suitable for the growth of cotton.

Xinjiang is lightly populated and has a vast planting area. It has    7    area of 1.66 million square kilometers and a population of about 23 million. The cotton planting area    8    （cover）25,019.3 square kilometers in 2020，according to the Department of Agriculture and Rural Affairs of Xinjiang.

The combination of advantaged    9    （nature）conditions and mechanical technology makes Xinjiang cotton have good quality. Endless white cotton has also become one of the    10    （symbol）of great beauty in Xinjiang.