【推荐1】The bristlecone pine (狐尾松) is one of the longest-living things on Earth. These trees, with their strangely shaped branches, can live up to 5,000 years, but experts worry that a warming climate in some areas may threaten its future.

Researchers say warmer weather is permitting a similar kind of tree, the limber pine (柔枝松), to take over good growing places from the ancient bristlecone. They say the tree is being forced out of mountainous areas where it grows.

Scientists at the University of California, Davis, say climate change is causing the trees to compete with each other.

Brian Smithers led the research project. “The limber pine is taking all the good spots,” he said.

Bristlecone pines grow in high mountain forests in eastern California, Nevada and Utah. In the mountains, they face high winds and extreme temperatures.

The difficult conditions leave the trees with twisted(变形的) branches and shapes. To survive long periods without water, parts of the trees die, including much of their outer bark (外皮). This makes the trees appear dead, except for small green pine needles. They show that the tree is indeed alive.

The oldest living bristlecone pine is somewhere in California. It is not marked in any special way, so that people do not try to damage it.

The limber pine is the bristlecone’s distant relative and competitor, which can also live a long time — up to 2,000 years. Researchers say it is found at lower elevations (纬度), where temperatures are warmer.

The scientists at the University of California, Davis, recently released the results of a three-year study. Their research centered on trees that have started growing in the last 50 years in the Great Basin area of California’s White Mountains. The researchers found that most of the trees growing at higher elevations were limber pines.

Smithers said, “It’s very strange to see it charging higher up and not see the bristlecone charging up the mountain slopes ahead of the limber pine.”

Smithers said the bristlecones are not in danger of disappearing, but he thinks they could be forced out of some places where they have grown for thousands of years.

1. What can we learn about the bristlecone pine from the text?
a. One of its living conditions is cold climate.   b. The shape of the tree is twisted.
c. It has the longest life in the world.       d. It can only be found in California.

A．ab.

B．bc.

C．ac.

D．cd.

2. What can we learn from the text?

A．The bristlecone pine can adapt to different environments.

B．The bristlecone pine grows at lower elevations.

C．Some bristlecone pines are still alive although their outer bark is dead.

D．The bristlecone pine’s habitat has been seriously damaged by humans.

3. What did the researchers find about trees that have started growing in the last 50 years?

A．The limber pine can live up to 2,000 years.

B．The higher elevations were almost taken up by limber pines.

C．The number of bristlecone pines is increasing.

D．The bristlecone pine grew at higher elevations.

4. What is Smithers’ opinion?

A．The bristlecone pine is in danger of disappearing.

B．Some measures should be taken to protect the bristlecone pine.

C．Some limber pines should be cut down to make room for the bristlecone pine.

D．Some places where the bristlecone pine used to grow may be occupied by the limber pine.

【推荐2】Biologists from the John Innes Centre in England discovered that plants have a biological process which divides their amount of stored energy by the length of the night. This solves the problem of how to portion out（分配） energy reserves during the night so that the plant can keep growing, yet not risk burning off all its stored energy.

While the sun shines, plants perform photosynthesis（光合作用）. In this process, the plants change sunlight, water and carbon dioxide into stored energy in the form of long chains of sugar, called starch（淀粉）. At night, the plants burn this stored starch to fuel continued growth.

“The calculations are precise so that plants prevent starvation but also make the most efficient use of their food,” said study co-author Alison Smith. “If the starch store is used too fast, plants will starve and stop growing during the night. If the store is used too slowly, some of it will be wasted.”

The scientists studied the plant Arabidopsis, which is regarded as a model plant for experiments. To give the plants some math tests, the biologists let night arrive unexpectedly early or late for them.

During one of the exams, they shut off the lights early on them that had been grown with twelve-hour days and nights. Putting them into darkness after only an eight-hour day means they didn’t have time to store as much starch as usual. And this forced the plants to adjust their normal nightly rhythm.

Amazingly, even after this day length trick, the plants did very well in their exams and ended up with just five percent of starch left over at the end of the night. They had neither starved, nor stored starch that could have been used to fuel more growth.

The authors suggested that similar biological calculators may explain how a migratory bird, the little stint, can make a five-thousand-kilometer journey to their summer habitat in the Arctic and arrive with enough fat reserves to survive only approximately half a day more, on average.

The results of the study were published in e Life.

1. According to the passage, plants _________.

A．use little energy during the day

B．usually stop growing at night

C．waste a lot of energy at night

D．store starch during the day

2. What did the scientists do when studying Arabidopsis?

A．They changed the plant’s light conditions.

B．They provided the plant with more starch.

C．They tried to keep the plant’s natural rhythm.

D．They attached a biological calculator to the plant.

3. When morning arrived, the experimental plants ________.

A．nearly died of lack of food

B．used most of their stored energy

C．began to regulate their food store

D．stored enough starch for the next day

4. What can we learn about the little stint?

A．They may have a system to control energy consumption.

B．They often die during their long and difficult journey.

C．They leave the Arctic in summer every year.

D．They are unable to calculate the distances.

5. The passage mainly tells us _________.

A．plants feel hungrier day by day

B．plants are good at storing energy

C．plants do math to survive the night

D．plants use starch to fuel their growth

【推荐3】Being scared is not always a treat. When a balloon pops, we may jump.     1     How does the body triggered（激发）these reactions? When we encounter something we're not familiar with, our brain and body start making changes to help prepare us for the unknown. These changes are part of the body's " threat," "stress," or "fight — or — flight" response. This response is triggered by the five senses, which are always sending information to the brain.     2    , the brain sounds a danger alarm. It releases chemicals into the bloodstream, and those chemicals act on different parts of the body. Once the body is alert（警觉的），the brain decides whether or not the danger is real.

    3     It urges a person to hide, run away, or defend oneself. Faster heartbeat and breathing send more blood and oxygen to the muscles so they're ready when they're needed. Stress chemicals can make a person more alert. Our memories also help protect us. We keep a close eye on babies because they don't understand what might hurt them. As babies grow, they learn what's unsafe, and their brains store those memories     4    

Experiences can lead to long-lasting fears that may stop a person from trying new things. We're born with the ability to feel fear, but a lot of what we're afraid of is learned. A long-lasting fear can mean you’re had a bad experience, and your brain doesn't want you to have it again. Many people have beaten their own fears. Here's one method.     5    , they learn the facts about anything that seems scary. Knowledge can help a person feel less afraid.

A．Instead of listening to their imagination

B．When they signal something unexpected

C．Our heart beats harder, and we breathe faster

D．Then their brains use fear to warn them of dangers

E．It's good to have a healthy sense of what's dangerous

F．Fear is a tool that the brain uses to keep the body safe

G．Memories are an important factor in fear-lasting experiences

【推荐1】People often talk about cultural differences between western and eastern countries, but how about the western world itself? Surprisingly, a closer look at it can reveal a good many curious details.

The most obvious characteristic of the majority of Americans is that they smile a lot. It does not matter whether they have a strong reason to smile；they do it，sometimes simply because they have to. A smile is not just a powerful marketing tool but also a way to show that someone is friendly，and that life in general is fine. Europeans, on the contrary(相反), prefer to keep a more neutral(不带感情色彩的)facial expression. They smile mostly when they are in a good mood，or feel amused；if not, a European's face will remain neutral, or even dull. In Russia, for example, there is a proverb saying that laughing for no reason is a sign of a fool. It does not mean that Europeans are serious, or that they do not have a sense of humor.

The same refers to communication in general. Americans are extremely communicative;small talks and chats are common. Europeans talk mostly when there is something to say, and rarely enter communication just for the purpose of talking to other people. American people prefer to express what they think carefully, considering how it might affect surrounding people. Europeans are more straightforward, even with unfamiliar people. A European friend will almost always voice his opinion on different occasions, and will not hesitate to remind you that you need to lose some weight or take a shower.

It can be said that Americans are people of contrasts. They are open­minded, flexible, and ready to accept everything new enthusiastically; but at the same time, American society manages to bring up unbelievable conservatives(保守者). Americans are extremely politically correct, which, in most cases, is indeed a secure and beneficial practice, but it can also mess up daily or even private communication, sometimes preventing having close relationships. Europeans, on the contrary, are more straightforward, preferring to tell the truth in direct ways. Each way of communication is different — neither is correct or incorrect.

1. What does the author say about smiling?

A．It is a powerful marketing tool across cultures.

B．It is culture­related within western countries.

C．It is thought of as a sign of a fool in America.

D．It is regarded as a social necessity in Europe.

2. What is typical of Europeans' communication?

A．Beating around the bush.	B．Hiding their feelings carefully.
C．Expressing themselves openly.	D．Having small talks and chats.

3. What does the underlined word “it” in the last paragraph refer to?

A．Being politically correct.

B．Being straightforward.

C．Accepting everything new.

D．Raising unbelievable conservatives.

4. How is the text mainly developed?

A．By making comparisons.	B．By analyzing cause and effect.
C．By classifying body language.	D．By discussing research findings.

5. What is the passage mainly talking about?

A．Ways of communication in American society.

B．Ways of communication in European society.

C．The differences between Americans and Europeans.

D．Cultural differences in Western countries.

【推荐2】How Sociologists Define Culture

Sociologists recognize that culture plays a crucial role in our social lives. It is important for shaping social relationships, maintaining social order, and in shaping our actions and experiences in society.     1    

In brief, sociologists define the non-material aspects of culture as the values and beliefs, language and practices that are shared in common. Expanding on these categories, culture is made up of our knowledge, common sense, the norms and morals; the symbols we use to express meaning and ideas.     2     It informs how we carry our bodies and interact with others; how we behave depending on the place, time and “audience”. Culture includes the practices we participate in as well, such as religious ceremonies and the celebration of holidays.

    3     This aspect of culture includes a wide variety of things, from buildings, technological gadgets and clothing, to film, music, literature and art, etc. Aspects of material culture are more commonly referred to as cultural products.

Sociologists see the two sides of culture — the material and non-material — as closely connected. Material culture emerges from the non-material aspects.     4     But it is not a one-way relationship between the two sides. Material culture can also influence the non-material aspects. For example, a powerful documentary film might change people’s attitudes and beliefs.     5     What has come before in terms of music, film, television and art influences the values and beliefs of those who interact with them, which then, in turn, influence the creation of additional cultural products.

A．Material culture is composed of the things that humans make and use.

B．This is why cultural products tend to follow patterns.

C．Without culture, we would not have relationships or society.

D．Culture is also what we do and how we behave and perform.

E．In other words, what we value and believe influences the things that we make.

F．Culture is distinct from social structure and economic aspects of society.

G．It is composed of both non-material and material things.