【推荐1】Many people with autism (自闭症) have trouble making eye contact, reading the emotions in other faces, and sharing affection. And no drugs are approved to treat such social impairments. Now, results from a Stanford University study suggest increasing levels of vasopressin (加压素) -a hormone (荷尔蒙) active in the brain known to promote bonding in many animals-can improve social deficits in children with autism.

Recently, Karen Parker, a scientist at Stanford University, and her colleagues have turned up evidence that monkeys that were less social had lower levels of vasopressin. The group also found children with autism who had the most social impairment had the lowest vasopressin levels.

The Stanford team gave a nasal (鼻的) spray containing vasopressin to 17 children with autism, aged 6 to 12 years. Another 13 children with autism served as a control group and got a placebo (无效对照的) spray, before and after the 4-week treatment, the research team asked parents to rate the children on a questionnaire called the Social Responsiveness Scale (SRS-2), which asks, for example, how often the children "would rather be alone than with others."

It turned out that vasopressin-treated children showed significantly more improvement-a seven-point-greater reduction-on the SRS-2 than those in the placebo group, the team reported in Science Translational Medicine. Those results "are very exciting," especially because the team didn't see major side effects, says Angela Sirigu, who is also investigating hormones for autism treatment.

Children with higher levels of vasopressin at the start of the study saw greater improvements. That's unexpected, Sirigu says—you'd expect children who were the most deficient in the hormone to benefit the most from the increase. Or maybe vasopressin is a marker for some other, yet-unknown feature of the children that predicts how much they'll improve with the treatment

The only weakness Pelphrey found with the Stanford study was its sample size: "if it were double, I would be jumping up and down." Still, he says, "I'm kind of rocking back and forth in my chair with excitement."

1. The underlined word "deficits" in the first paragraph can be replaced with      .

A．advantages

B．surplus

C．weaknesses

D．strengths

2. What is Paragraph 3 mainly about？

A．the purpose of the experiment	B．the samples of the experiment
C．the principle of the experiment	D．the method and steps of the experiment

3. According to the results of the Stanford study, increased vasopressin      .

A．had no side effect on children with autism

B．most benefited children with the most social impairment

C．had a positive effect on children in the test group

D．had a negative impact on children in the test group

4. What is the Stanford group most likely to do to perfect their study？

A．Run another trial of vasopressin enrolling 100 children.

B．Give tested children a longer treatment to reach the maximum benefits.

C．Decrease vasopressin in tested children to see the opposite results.

D．Increase vasopressin in adults with autism to see its influence.

【推荐2】In sports, sometimes a player has to take one for the team. The same appears to be true in the plant world, where reduced individual growth can benefit the broader community. The findings from the University of Michigan’s Paul Glaum and André Kessler of Cornell University help explain the persistence (持续存在) of some plant communities when theory predicts they should go extinct(绝种的).

“We looked at how chemical defense cues (信号) from plants, meant to prevent herbivores (食草动物), can also prevent pollinators,” said Glaum, a doctoral student in the U-M Department of Ecology and Evolutionary Biology. “The surprising model result is that while this can lead to fitness losses for individuals, the population effects can be positive for pollinators and plants under some circumstances.”

Many plants, including the wild tomato species used in this study, produce chemical compounds to repel (排斥) insect pests and other hungry herbivores. But those same chemical defenses can reduce the number of visits to the plant by pollinators such as bees, resulting in less pollination of individual plants and decreased growth.

“Biologists have puzzled over how such a costly defense mechanism (机制) can be maintained in these plant populations,” Glaum said. “How would a plant population with such a strategy persist?” Glaum and Kessler developed a computer model showing that decreased growth of individual plants can benefit overall populations and community resilience (恢复力) by indirectly controlling herbivore population growth. The results introduce mechanisms of persistence into communities previously found to be prone (易于遭受的) to extinction in theoretical models.

Tomatoes and other plants produce repellent chemicals called volatile (易挥发的) organic compounds in response to herbivore attacks. The presence of these so-called herbivore-induced volatile organic compounds can make the plant less attractive to pollinators, which can reduce pollen deposition (沉淀物) and negatively affect individual plants, an effect known as herbivore-induced pollinator limitation.

Previous modeling studies have looked at the direct effects of herbivory on a three-species community: flowering plant, pollinator and herbivore. Some of those studies predicted extinctions because growing herbivore populations would reduce the number of plants, limiting resources available to pollinators. In response, the pollinator population would decline, lowering plant reproduction.

1. According to the passage, the persistence of some plant communities may depend on __________.

A．chemical defenses of plants	B．increased individual growth
C．reduced chemical compounds	D．defense mechanisms of pollinators

2. The underlined word pollinator in Paragraph 2 probably refers to __________.

A．a kind of insects that help plants reproduce	B．a kind of animals that eat plants
C．a process of forming a plant community	D．a chemical that does harm to plants

3. Volatile organic compounds are __________.

A．less attractive to pollinators

B．able to have negative effects on individual plants

C．known as herbivore-induced pollinator limitation

D．chemicals produced by plants to attract herbivores

【推荐1】Plants cannot run or hide, so they need other strategies to avoid being eaten. Some curl up their leaves, others produce chemicals to make themselves taste bad if they sense animals drooling on them, chewing them up or laying eggs on them—all signals of an attack. New research now shows some flora can feel a plant-eating animal well before it launches an attack, letting a plant prepare a preemptive（先发制人的）defense that even works against other pest species.

When ecologist John Orrock of the University of Wisconsin-Madison sprayed snail slime—a liquid the animals release as they slide along—onto soil, nearby tomato plants appeared to notice. They increased their levels of an enzyme（酶）, which is known to prevent plant-eating animals. “None of the plants were ever actually attacked,” Orrock says. “We just gave them cues that suggested an attack was coming, and that was enough to cause big changes in their chemistry.”

Initially Orrock found this defense worked against snails; in the latest study, his team measured the slimy warning’s impact on another potential threat. The investigators found that hungry caterpillars（毛虫）, which usually eat tomato leaves greedily, had no appetite for them after the plants were exposed to snail slime and activated their chemical resistance. This nonspecific defense may be a strategy that benefits the plants by further improving their overall possibilities of survival, says Orrock, who reported the results with his colleagues in March in Oecologia.

The finding that a snail’s approach can cause a plant response that affects a different animal made Richard Karban curious, a plant communications expert, who was not involved in the study. “It is significant that the plants are responding before being damaged and that these cues are having such far-ranging effects, ” Karban says. The research was comprehensive, he adds, but he wonders how the tomato plants felt chemicals in snail slime that never actually touched them.

“That’s the million-dollar question,” Orrock says. He hopes future research will make out the mechanisms that enable plants to sense these relatively distant cues.

1. John Orrock sprayed a liquid onto soil near tomato plants to ________.

A．make them grow better

B．give them a warning

C．keep plant-eating animals away

D．inform plant-eating animals of danger

2. Why is the example of “caterpillars” mentioned in Paragraph 3?

A．To introduce another animal.

B．To confirm the result of the study.

C．To appeal to people to protect animals.

D．To analyze different resistance chemicals.

3. What does Richard Karban really want to know?

A．How tomato plants become aware of danger.

B．What the chemicals in the snail slime are.

C．Whether the research is of practical value.

D．What the finding of the research is.

4. What can be a suitable title for the text?

A．Watchful Plants.	B．Greedy Animals.
C．A Snail’s Approach.	D．A Defense Attack.

【推荐2】阅读七选五

Trees around us are extremely important and have always been necessary for improving the human conditions. Our existing forests and trees we plant work to make a better world.    1    . Here is a short list of main reasons trees are necessary for improving our living conditions.

Trees produce oxygen    2    . A leafy tree produces as much oxygen in a season as 10 people inhale in a year. What many people don't realize is that the forest also acts as a giant filter (过滤器) that cleans the air we breathe. Trees help clean the air by preventing airborne particles, reducing heat, and absorbing such pollutants. Trees clean the soil. The term phytoremediation is a fancy word for the absorption of dangerous chemicals and other pollutants that have entered the soil.

    3    . Trees filter sewage and farm chemicals, reduce the effects of animal wastes, clean roadside spills and so on. Trees are carbon sinks. To produce its food, a tree absorbs and locks away carbon dioxide in the wood, roots and leaves.

Carbon dioxide is a global warming suspect.    4    . This locking­up process “stores” carbon as wood and not as a “greenhouse” gas.

    5    Trees block urban noise almost as effectively as stone walls. Trees, planted at strategic points in a neighborhood or around your house, can reduce major noises from freeways and airports.

A．We could not exist as we do if there were no trees

B．Trees help clean the sky

C．A forest is a carbon storage area that can lock up as much carbon as it produces

D．Trees control noise pollution

E．Man has been planting trees to make the planet a more beautiful world

F．The modern human community has other more practical reasons to admire and honor trees

G．Trees can either store harmful pollutants or change the pollutants into less harmful forms

【推荐3】An ancient plant, amaranth(苋菜),is drawing attention throughout the world and connecting indigenous people(土著人)to their history. It has become a billion-dollar food and cosmetic product since the 1970s. The ancient grain can be found in greater numbers of grocery stores in the US and Mexico, and increasingly in the Asia Pacific and Europe.

“This is a plant that could feed the world.” Beata Tsosie-Pena, a coordinator of the environmental, health and justice program at nonprofit Tewa Women United, told The Guardian.                      

Amaranth is actually a grain, like buckwheat, and native to Mesoamerica, a region including southern Mexico and many counties in Central America. Its seed is a highly nutritious source of protein, vitamins and minerals. It’s proved to be an attractive product for health-conscious shoppers.

A single amaranth plant produces hundreds of seeds and can be grown in a wide variety of climates and countries from India, China, Southeast Asia to West Africa and the Caribbean. It’s this resilience that allowed the plant to survive over the centuries, even when the Spanish arrived in the Americas in the 16th century and outlawed amaranth. Growing amaranth has also provided a degree of economic independence for indigenous farmers in Guatemala and the US, according to The Guardian. Even after facing a near-extinction event in Guatemala when state forces targeted the Maya people and burned their fields, farmers preserved their amaranth seeds by hiding them in jars in the field and under their floorboards.

“What we want is for the whole world to produce their own food,” Maria Aurelia Xitumul, a. member of agricultural community Qachuu Aloom, told The Guardian. ”For the seeds, distance doesn’t exist. Borders don’t exist.” Most recently, Xitumul said that during the pandemic, people with their own gardens, especially in locked down communities, felt secure knowing they had control over their food supply, thanks to amaranth.

“Amaranth has completely changed the lives of families in our communities, not only economically, but spiritually,” added Xitumul.

1. What do we know-about amaranth?

A．It was found in Mesoamerica in the 1970s.

B．It mainly grows in the Americas and Europe.

C．Its seed contains abundant vitamins and minerals.

D．It’s one of the most expensive foods in the world.

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

A．Its ability to produce many seeds.

B．Its function of offering economic independence.

C．The quality of growing quickly in extreme weather.

D．Its ability to adjust to different environments.

3. What does Xitumul point out?

A．Plants should be grown in line with local conditions.

B．Countries should work together to promote the seeds.

C．Amaranth gave people a sense of security during lockdown.

D．Amaranth helped lift many families out of poverty.

4. Which of the following can be the best title of the passage?

A．The Origin of Amaranth.

B．The Value of Amaranth.

C．The Popularity of Amaranth.

D．The Wide Application of Amaranth.