1 . Scientists have shown how plants can protect themselves against genetic (基因的) damage caused by environmental stresses. The growing tips of plant roots and shoots have an in-built mechanism (机制) that spells cell death if DNA damage is detected, avoiding passing on faulty DNA.

Plants have small populations of stem cells (干细胞) at the tips of their roots and shoots, which enable them to continuously grow and produce new tissues throughout their lifetime. These stem cells serve as ancestors for plant tissues and organs. However, any genetic faults present in the stem cells will continue to exist and be passed on permanently throughout the plant’s life, which could last thousands of years.

Given the critical role of stem cells and their exposure to potentially dangerous environments at the growing tips of roots and shoots, safeguards are necessary to prevent stem cell faults from becoming fixed. Researchers Nick Fulcher and Robert Sablowski, funded by the Biotechnology and Biological Sciences Research Council, aimed to uncover these protective mechanisms. Through experiments involving X-rays and chemicals, they discovered that stem cells were more sensitive to DNA damage compared to other cells.

When DNA damage occurs, the cells have the capacity to detect it and cause programmed cells to die, preventing the propagation of the damaged genetic code to the rest of the plant tissues. This process has similarities to the safeguard mechanism found in animal cells, which has been broadly studied due to its relevance in preventing cancer.

The identification of a similar protective system in plants is of great interest in the field of plant development. It also helps scientists develop plants that can better handle environmental stress. So knowledge of how plants deal with these stresses is of fundamental significance to agricultural science’s response to climate change.

1. What is the function of the in-built mechanism in plants?

A．To produce more roots and shoots.	B．To increase the overall lifetime of the plant.
C．To enhance plant growth and nutrient intake.	D．To stop genetic faults in stem cells passing on.

2. What can we know about stem cells in plants according to the text?

A．They are relatively abundant in quantity.	B．They are resistant to environmental stresses.
C．They make quick response to DNA damage.	D．They have the ability to repair damaged DNA.

3. What does the underlined word “propagation” in paragraph 4 mean?

A．Spread.

B．Change.

C．Existence.

D．Self-repair.

4. What does the last paragraph focus on?

A．The way of dealing with climate change on the earth.

B．The significance of identifying the protective system in plants.

C．The method of ensuring plant survival under environmental stress.

D．The urgency of developing plants that can handle environmental stress.

2 . When micro-plastics end up in farm fields, the pollution can damage plant growth. But two young researchers now report that combining fungi (真菌) with certain farm wastes can partly overcome that problem.

May Shin, 20, and Jiwon Choi, 18, met in a research design class at the Fryeburg Academy, a high school in Maine. May had desired to explore how micro-plastics might affect the ecosystem. Jiwon was crazy about plants and fungi. The young scientists cooperated to test how long-lived plastics might affect farm crops.

Scientists have shown certain fungi can aid root growth and a plant’s nutrient uptake. Those organisms are named arbuscular mycorrhizal fungi (AMF). Certain farm wastes, like straw, can provide nutrients to plants and help stabilize their roots. Such wastes are also known as mushroom substrate (基质) and people often grow mushrooms in them.

May and Jiwon planted over 2,000 scallion (大葱) seeds in pots of soil. Half the seeds got soil polluted with micro-plastics. The rest grew in plastic-free soil. The plants then were further divided into four groups. The young scientists added AMF to the soil in one group. Another group had a top layer of mushroom substrate. A third group got both treatments. The last group got none. For three weeks, the pair tracked how many scallions sprouted (发芽) in each group and measured the plants’ height once each week.

About twice as many scallions sprouted in clean soil compared to that containing plastic bits. But among plants surviving in the polluted soil, a combination of AMF and mushroom substrate helped them out. Those getting both treatments grew 5.4 centimeters per week. That was faster than either of the treatments alone or those getting none.

Jiwon and May then looked at the plant roots with a microscope. Where AMF had been added, it grew into those roots. That increased the scallion roots’ surface area, May said, which should promote their uptake of nutrients. So “I see this project as coming up with a sustainable solution for plant growth in polluted soils,” said May.

1. Why did May and Jiwon work together?

A．To see the effects of long-lived plastics on farm crops.

B．To find the relationship between plants and fungi.

C．To design a research on the growth of plants.

D．To explore the way that the ecosystem works.

2. What is the author’s purpose in writing paragraph 3?

A．To prove the existence of micro-plastics.	B．To compare fungi with farm wastes.
C．To tell the advantages of farm wastes.	D．To provide some related information.

3. What aspect of the study is the fourth paragraph mainly about?

A．Its purpose.

B．Its design.

C．Its findings.

D．Its reasons.

4. How can AMF and mushroom substrate make plants grow faster?

A．By keeping the plants more resistant to pollution.	B．By allowing the plants’ deep area more freedom.
C．By making nutrients more available to the plants.	D．By exposing the roots to a larger surface area.

3 . When I was a kid, a sycamore (枫树) grew in front of my home. At the age of 10, I was just tall enough to reach its lowest branch and lift myself into its embrace. Sometimes two or three of my friends would join me in the sycamore, or in the maple down the street, or Mrs. DiMarco’s old peach tree, some of whose stout horizontal branches allowed us to sit shoulder to shoulder, eating sweet fruit.

In my small town there are some kinds of trees, their branches spreading wide, open for business. But I have not yet seen a climber. Perhaps computer games have replaced tree climbing, or maybe the activity went the way of monkey bars, which came to be viewed as too risky and have largely disappeared from playgrounds.

It is a sad loss. I have always believed that, since low-hanging branches provide no benefit to the tree, they must be meant for the child. Robert Frost understood this when he wrote:

When I see baches (桦树) bend to left and right,

Across the lines of straighter darker trees,

I like to think some boy’s been swinging them.

My only disagreement with Frost is his inference that tree climbing is a gender-specific task. Both boys and girls make a joyful climb.

The campus of the university where I teach has all sorts of trees. During a recent walk, I found myself bending under the branch of an immense spruce (云杉). I grabbed the thing, and a moment later was sitting on a branch. Then the memories came flooding back. The old sycamore, the friends, and finally, the reluctance to return to earth when the parental call to supper came.

I was so lost in my thoughts that I didn’t hear the student calling to me from below. He asked what I was doing. I didn’t waste time on explanations. “Come on up,” I said “The air’s fine.” But he only laughed and waved me off. He didn’t know what he was missing.

1. What does the underlined word “stout” in Paragraph 1 probably mean?

A．Slim.

B．Bent.

C．Smooth.

D．Strong.

2. What is the second paragraph mainly about?

A．Why kids don’t climb trees.

B．Why monkey bars are dangerous.

C．Why there is no business under trees.

D．Why kids are addicted to computer games.

3. What does the author want to prove by mentioning Robert’s poem?

A．Some branches of trees are useless.

B．Trees are intended for kids to climb.

C．Trees are a source of inspiration for poets.

D．Climbing trees is a unique right of boys.

4. What did the author think the student had missed?

A．The explanations to his question.

B．The fresh air above the tree.

C．The pleasure of climbing trees.

D．The sense of safety on earth.

4 . Now, a study proves that gardens are more than just a pretty place. The study, by researchers at Illinois State University, demonstrates that such constructed gardens can have a measurable and positive impact on water quality.

Floating gardens are essentially platforms built and wrapped in coconut husks (椰子壳), and filled in with native plantings. As plants grow, they extend their roots into the water. On the North Branch of the Chicago River, non-profit Urban Rivers and its partners are developing a mile-long floating eco-park called the Wild Mile. The re-development of this former industrial canal is Urban Rivers’ important project. As part of the park, floating gardens, attached to shore, are being fixed.

The primary aim of the floating gardens is beautification. But the Illinois State team, from the University’s Department of Geology, Geography, and the Environment, saw an ideal setup for a controlled experiment. “We joined it because it’s the perfect opportunity to see if there’s an influence on water quality,” explains lead author Abigail Heath.

The study is novel: previous studies have explored floating gardens’ influence on water quality over time, primarily in wastewater treatment ponds, but not over space, in moving water. The project also matches well with Urban Rivers’ broader goals. “The city is interested in bettering water quality,” says Phil Nicodemus, Urban Rivers’ Director of Research. “Happily, Illinois State took part in it later.”

Could this small human-made park improve water quality? An average of data collected over the course of the study shows middle but definitive improvement. For example, nitrogen (氮) dropped from 4.69 milligrams per liter in surface water to 4.43 milligrams per liter, a drop of about 1 percent.

“Despite how small this garden was, there was measurable improvement in water quality from upstream to downstream,” notes Heath. She and her colleagues see this as a model for how large floating gardens should be to help improve water in similar settings. “Even this tiny garden makes a difference,” she says.

1. What can be inferred from the second paragraph?

A．The floating gardens are environmentally friendly.

B．The floating gardens are fixed everywhere in the eco-park.

C．The floating gardens can help fix the former parks.

D．The Urban Rivers were once industrial canals.

2. What is the main reason to build the floating gardens?

A．To reduce waste water.	B．To attract more visitors to the park.
C．To make the surroundings brilliant.	D．To help researchers do the experiment.

3. What does the underlined word “it” refer to in Paragraph 4?

A．The floating garden.	B．The project.
C．The treatment of ponds.	D．The quality of water.

4. Which of the following could be the best title for the text?

A．Floating Gardens: More than Pretty

B．The Best Way to Better Water Quality

C．A Practical Method of Improving Parks

D．Floating Gardens Beautify the City

5 . Fig trees are native to Europe around the Mediterranean Sea, Asia and Arica, but they can grow in much cooler climates.

Once big enough, fig trees can accept temperatures even a few degrees below freezing. Some kinds of fig trees do better in such environments than others.

Depending on the weather and pruning (修剪), a fig can grow into a bush or a tee. Bushes with several stems (茎) growing from the ground do best if covered for the winter.     1    Either way, wait until the trees have dropped most of their leaves.

One popular method for burying trees for their protection involves digging a narrow, shallow area.     2    The space should be about 30 centimeters deep, 60 centimeters wide and as long as the height of the tree. To prepare the tree, gather its branches and tie them together with soft rope.

Next, push a shovel (铲子) into the soil about a half-meter from the trunk (树干) on the side opposite the hole. Lift that side of the tree’s root ball out of the ground. Then, gently push the tree toward the hole.    3    

Pack soil around the exposed side of the roots, and around the length of the tree. Load soil over the tree. Make it at least 30 centimeters deep. You will need more soil than you removed from digging.

    4    In this case, you should work upwards from the bottom and put cloth around the tree. Then put heavy brown paper around the cloth and tie it into place. Remove some soil from around the base of the tree. Place a large piece of cardboard into the space.     5    Tie the cardboard into place.

A．And in this area the tree can be laid.

B．All kinds of the trees could use protection.

C．You can also cover, or wrap, the tree instead.

D．And bend it around the bottom part of the tree.

E．When it is lying fat, cover the tree with plastic.

F．Trees with a single trunk can be buried or covered.

G．Remove the cover on the tee on a cloudy day in early spring.

6 . There are many theories that suggest different ways of improving memory or thinking more clearly. One of those is the idea that adding rosemary (迷迭香) to your food or water, or even breathing in its fragrance, can give your brain a boost.

First, it’s important to understand what rosemary is.     1     It’s a perennial, meaning that once you plant it, it should re-grow every year when the weather is warm enough for it to do so. It’s native to Asia and the Mediterranean.     2    

Rosemary is related to the mint (薄荷) family of plants. When it blooms, its flowers are white, purple, pink or deep blue. It is often used as a flavor in food, including soups, meat, fish and other Mediterranean food. And it has a somewhat bitter flavor. Some people also enjoy tea flavored with rosemary.     3    

One study that involved 28 older adults found that consumption of a small amount of dried rosemary powder was associated with statistically significantly improved memory speed.     4     Researchers found that their memory of images and numbers improved when the essential oil of rosemary was sprayed in the room.

    5     But one theory is that rosemary appears to have some antioxidant (抗氧剂) properties that may offer some healing for the damage in our bodies. Another idea is that rosemary appears to lower anxiety, which in turn, may increase the ability to concentrate.

While rosemary shows some promise for boosting our brain power, it’s important to check with your doctor before you begin having it.

A．But it is grown in the United States, as well.

B．Rosemary is a herb with needle-like leaves.

C．Here’s what research has found about rosemary.

D．It is unknown if those benefits would hold true for humans.

E．It’s not known for sure why there may be a benefit from rosemary.

F．Rosemary is also used as a perfume and added to shampoo and soap.

G．Another study was performed with 53 students between 13 and 15 years old.

7 . In ancient Greece, purslane herb (马齿苋) was regarded as an important medicinal herb for treatment of fever, female disorders, stomachaches, and headaches, and Hippoctrates, the famous father of medicine, practically tried it for the healing of wounds. Purslane herb was later considered as a cold herb around the 17th. Century.

Purslane is today known as a beneficial juicy herb found as a weed throughout the world. Purslane is commonly used as an ingredient for salads. Purslane has been recently identified as an excellent source of alpha-linolenic acid (亚麻酸). Alpha-linolenic is a kind of an omega-3 fatty acid, also known as fish oil. This important content in purslane herb plays an important role in human growth, development and preventing disease. Modern medical research claims that purslane herb is five times richer in omega-3 fatty acids than another vegetable, and also is high in vitamin C.

Purslane has small, green leaves, which are usually delicate and juicy. The stem is round and smooth. Young plants have a green stem but as the plant matures the stems take on reddish colors. Flowers are 1/4 inch long and a brilliant yellow in color with 5 petals (花瓣), which contain round black seeds. Purslane herb presents a wide variety of medical uses and each part of the herb is beneficial. Purslane herb is widely used all over the world and here is its known benefit: Purslane is known as an excellent source of vitamins C and E and the essential alpha-linolenic acids.

Reports describe purslane as power food of the future because of its high value of nutrition and medicine. Purslane leaves contain Omega-3 fatty acids which regulate the metabolic (新陈代谢) activities of bodies. The stems of purslane herb are known to be high in vitamin C. Purslane-herb is known to have one of the best known concentrations of Omega-3 fatty acid.

1. In ancient Greece, Hippoctrates used purslane to treat ________.

A．Stomachaches

B．Wounds

C．Headaches

D．Fever

2. Which is the correct description of purslane?

A．Its stems are round and strong.

B．Its leaves are big and green.

C．Its stems are red in color.

D．Its flowers are yellow in color.

3. Why is purslane considered as power food of the future?

A．Because its leaves are rich in vitamin C.

B．Because its stem contains Omega-3 fatty acids.

C．Because it is valuable in nutrition and medicine.

D．Because it regulates the metabolic activities of bodies.

4. What is the best title for this passage?

A．Purslane, a famous herb in the world

B．The basic knowledge about purslane

C．Purslane, a herb that benefits health

D．The medical research about purslane

8 . In organic（有机的) farming, crops, meat and other food are produced without chemicals. Fertilizers, and antibiotics (化肥与抗生素) are not allowed. During thousands of years of civilization the raising of animals and growing of plants have always been organic.

Chemicals for farming first came up at the turn of the 20th century. Widespread use of chemicals began after World War II. In the 1950s and 60s farmers started using chemical fertilizers and antibiotics. Recently, however, more and more farmers have been returning to more natural ways of producing farm products.

Instead of chemicals, organic farming uses a lot of organic matter to give crops the nutrients that they need to grow. Clover, for example, has a lot of nitrogen (氮) in it and farmers use it to make the soil better. Manure from animals and compost (混合肥料) are also used to enrich the soil. These fertilizers also help protect the soil, not destroy it after a few years.

Organic farmers also use crop rotation (轮作) to protect the good qualities of soils. Chemical antibiotics destroy or weaken many of the natural enemies of pests, like birds or frogs. They also can kill those insects that control a great number of pests. Organic farming creates new living areas for little animals, such as wasps, bugs, beetles and flies by giving them water and food. Weeds are controlled by using special machines. Hay, straw and wood chips are put between the rows of plants to stop weeding.

Many agricultural products can be produced in an organic way. Meat, dairy products and eggs come from animals that are fed organically and can graze outdoors. They live in conditions that are natural to them. Cows, for example, are kept in pastures and fields. Vegetables and fruit are also produced with organic methods.

1. What of the following best describes the organic farming?

A．Time-saving.

B．Environmental.

C．Productive.

D．Developmental.

2. What does the underlined word “Manure” in paragraph 3 probably mean?

A．Crop roots.	B．Chemical fertilizers.
C．Animals’ waste.	D．Agricultural products.

3. What is the fourth paragraph mainly about?

A．The new study of soils.	B．Benefits from organic farming.
C．A breakthrough in antibiotics.	D．Natural enemies of animals.

4. Which of the following can be the best title for the text?

A．Organic farming and food	B．Importance of organic methods
C．Benefits of organic fertilizers	D．Strengths of manure and compost

9 . 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

10 . High on the top of California's White Mountains, the hard conditions make it difficult for life to take root. But for a certain type of tree — and for those who have travelled here to study it — this place is a perfect place.

These bristlecone pines are the oldest individual trees in the world. Researchers like Andy Bunn have come to learn from the ancients. "It's remarkable to sit here and have your hand on one of these trees and know that it was growing when the Pyramids were built." Bunn added.

"By studying samples (样本) from the trunks, it's possible to discover their hidden history. Each annual tree ring is like a time capsule of the environment for that year from which it was formed," said Matt Salzer, a scientist at the University of Arizona's Laboratory of Tree Ring Research. "And it contains many different types of information — chemical information, the information on growth, and climate information."

"If you're trying to look at people in the past through time, tree rings give you a way to do it in a way that makes sense in a human life," said University of Arizona Professor Charlotte Pearson. She first became fascinated with the bristlecones after reading about an ancient volcanic eruption on the Greek island of Santorini. "It blew my mind that trees on the other side of the world could possibly be used to date this thing within a single year," she said excitedly.

The oldest known living bristlecone is estimated to be over 4, 800 years old. For Bunn, the climate record written in the rings offers guidance for how we might think about what's happening in the present as we plan for the future. "What we're seeing increasingly is that a lot of the climate events that we are experiencing and living through right now have no example in the paleoclimate (古气候) record," he said. “So, we really are moving into unknown field."

1. Why does Bunn mention the Pyramids in Paragraph 2?

A．To state the trees' age is very old.	B．To prove his discovery is important.
C．To attract readers' attention.	D．To stress the hard living condition of the trees.

2. What's the third paragraph mainly about?

A．The result of the research.	B．The process of the research.
C．The method of the research.	D．The significance of the research.

3. What do the underlined words "It blew my mind" in Paragraph 4 probably mean?

A．It confused me.	B．It surprised me.
C．It defeated me.	D．It disappointed me.

4. What can we infer from the last paragraph?

A．Paleoclimate record is hard to find.

B．There are lots of unknown things about pines.

C．Studying the tree rings is important for climate research.

D．There were frequent occurrences of the extreme climate events.