Scientists have long wondered parts of the br...

Scientists have long wondered　　parts of the brain are involved in musical tasks.

A. that            B. which            C. whose            D. where

高三英语单项填空中等难度题查看答案及解析

Scientists have exactly discovered the set of brain cells involved in making risky decisions, and have been able to control them in rats using targeted light. By changing the activity of the cells they were able to change the behaviour of risk-taking rats to avoid risk, hinting the approach could in future be used to treat people with impulse (冲动) control problems.

Risk-taking is a key part of survival, knowing when to take a chance could pay off—such as moving to a new area to look for food when pickings are slim.

While all animals need an element of risk, the preference towards it varies between individuals. Researchers found this variation, which determines how risk-averse an individual is, is regulated by brain cells in a region of the brain called the nucleus accumbens. This cluster of neurons releases the neurotransmitter dopamine, which regulates the brain’s reward and pleasure centres.

Previous studies have shown that in patients with Parkinson’s disease, taking medication which blocks specific dopamine receptors (DR2) (受体) leads to increased gambling (赌博) behaviour and risk taking behaviour. In studies with rats, researchers were able to use a technique called optogenetics (光遗传学)—which uses light sensitive proteins to change the activity of cells—to modify cells with DR2 in the nucleus accumbens.

Rats were trained to choose one of two levers, offering them a choice between a “safe” or “risky” choice. The safe option resulted in a small, but consistent amount of a sugar water treat. But the risky choice consistently delivered smaller amounts of sugar water, with the occasional large pay off—essentially encouraging the animals to gamble for a bigger prize. Around two-thirds of the animals weren’t keen on risk, opting for the safe option, but the remaining third were risk-seekers. Brain scans of the animals showed that those with low levels of DR2 consistently went for the gamble.

But using pulses of light to stimulate (刺激) the DR2 cells and improve their activity could cause the risk-takers to play it safe and opt for the guaranteed but less rewarding option. Once the light-pulses stopped, the risk-takers returned to their gambling strategy.

In the risk-averse animals, stimulating the same cells had little to no effect.

Professor Karl Deisseroth, of Stanford University in California, said: “Humans and rats have similar brain structures involved.”And we found a drug known to increase risk preference in people had the same effect on the rats. So every indication is that these findings are relevant to humans. “Risky behavior has its moments where it’ s valuable. As a species, we wouldn’t have come as far as we have without it.”

1.The variation in people’s preference towards risks is directly regulated by ________.

A. nucleus accumbens　　　 B. light sensitive proteins

C. neurons　　　 　　　　　　 D. dopamine

2.From the experiment with rats, we can conclude that ________.

A. the lack of DR2 cells results in a safe option

B. the levels of DR2 have little to do with their choices

C. the high levels of DR2 can make animals avoid risks

D. the risky choice is a less rewarding option

3.The underlined words in Paragraph 7 most likely mean the animals that are ________.

A. willing to take big risks

B. reluctant to take risks

C. fond of gambling strategy

D. afraid of receiving stimulation

4.What can be inferred from what Professor Karl Deisseroth said?

A. Humans and rats differ in their preference for risk-taking.

B. Too much risk-taking can do more harm than good.

C. Risk-taking can be used to treat people with impulse control problems.

D. Risk-taking is a means of survival and brings higher returns to humans.

高三英语阅读理解中等难度题查看答案及解析

Scientists have exactly discovered the set of brain cells involved in making risky decisions, and have been able to control them in rats using targeted light. By changing the activity of the cells they were able to change the behaviour of risk-taking rats to avoid risk, hinting the approach could in future be used to treat people with impulse (冲动) control problems.

Risk-taking is a key part of survival, knowing when to take a chance could pay off—such as moving to a new area to look for food when pickings are slim.

While all animals need an element of risk, the preference towards it varies between individuals. Researchers found this variation, which determines how risk-averse an individual is, is regulated by brain cells in a region of the brain called the nucleus accumbens. This cluster of neurons releases the neurotransmitter dopamine, which regulates the brain’s reward and pleasure centres.

Previous studies have shown that in patients with Parkinson’s disease, taking medication which blocks specific dopamine receptors (DR2) (受体) leads to increased gambling (赌博) behaviour and risk taking behaviour. In studies with rats, researchers were able to use a technique called optogenetics (光遗传学)—which uses light sensitive proteins to change the activity of cells—to modify cells with DR2 in the nucleus accumbens.

Rats were trained to choose one of two levers, offering them a choice between a “safe” or “risky” choice. The safe option resulted in a small, but consistent amount of a sugar water treat. But the risky choice consistently delivered smaller amounts of sugar water, with the occasional large pay off—essentially encouraging the animals to gamble for a bigger prize. Around two-thirds of the animals weren’t keen on risk, opting for the safe option, but the remaining third were risk-seekers. Brain scans of the animals showed that those with low levels of DR2 consistently went for the gamble.

But using pulses of light to stimulate (刺激) the DR2 cells and improve their activity could cause the risk-takers to play it safe and opt for the guaranteed but less rewarding option. Once the light-pulses stopped, the risk-takers returned to their gambling strategy.

In the risk-averse animals, stimulating the same cells had little to no effect.

Professor Karl Deisseroth, of Stanford University in California, said: “Humans and rats have similar brain structures involved.”And we found a drug known to increase risk preference in people had the same effect on the rats. So every indication is that these findings are relevant to humans. “Risky behavior has its moments where it’ s valuable. As a species, we wouldn’t have come as far as we have without it.”

1.The variation in people’s preference towards risks is directly regulated by ________.

A. nucleus accumbens　　　 B. light sensitive proteins

C. neurons　　　 　　　　　　 D. dopamine

2.From the experiment with rats, we can conclude that ________.

A. the lack of DR2 cells results in a safe option

B. the levels of DR2 have little to do with their choices

C. the high levels of DR2 can make animals avoid risks

D. the risky choice is a less rewarding option

3.The underlined words in Paragraph 7 most likely mean the animals that are ________.

A. willing to take big risks

B. reluctant to take risks

C. fond of gambling strategy

D. afraid of receiving stimulation

4.What can be inferred from what Professor Karl Deisseroth said?

A. Humans and rats differ in their preference for risk-taking.

B. Too much risk-taking can do more harm than good.

C. Risk-taking can be used to treat people with impulse control problems.

D. Risk-taking is a means of survival and brings higher returns to humans.

高三英语阅读理解中等难度题查看答案及解析

Scientists don’t know yet whether cell phones are bad for the brain.1.

In the experiment, the 47 participants may have looked a little strange. Each of them had two Samsung cell phones tied to his or her head—one on each ear.2.　 The phone on the right　 ear played a message for 50 minutes, but the participants couldn’t hear it because the sound was off. After 50 minutes with two phone attached to their heads, the participants were given PET scans. The PET scan is a way to take a three-dimensional picture of how the inside of the bodyworks.

The PET scan showed that the left side of each participant’s brain hadn’t changed from the way it was before the experiment.3. These right-side brain　 cells were　 using　 almost　 as　 much glucose as the brain uses when a person is talking. This suggests that brain cells there were active even without the person hearing or talking anything. This activity, the scientists say, was probably touched off by radiation from the phone.

4. They release different amounts of radiation depending on whether a person　 is　 talking or listening, the type of phone, the number of people using phones nearby, and the distance to the nearest cell phone tower. All of these changes make it difficult to collect evidence about any health risks of cell phones, since exposure to radiation can vary.

So for those who don’t want to wait to find out for sure whether cell phones are bad for the brain, there are ways to talk more safely.5.

A.The phone on the left ear was off.

B.So an experiment was done to attempt to find it out.

C.People should avoid having a long conversation by using cell phones.

D.Cell phones do not always give out the same amount of energy.

E.You can have short conversations, use a speakerphone to keep the phone away from your head.

F.The right side of the brain, however, had used more glucose, which provided fuel to brain cells.

G.From the PET scan the differences between the two sides of the brain were observed.

高三英语七选五中等难度题查看答案及解析

(2013·青岛一模)Scientists are still wondering ________ the Egyptians built the pyramids so long ago.

A．how it is that      B．how is it that

C．it is how that      D．that how it is

高三英语单项填空中等难度题查看答案及解析

Scientists are not sure how the brain follows the tracks of time．One theory holds that it has a group of cells specialized to record the intervals （间隔）of time, while another theory holds that some neural processes （神经突）act as an inside clock．

Whichever theory it may be, studies find, the cells have a poor grasp of longer interval．Time does seem to slow during an empty afternoon and race when the brain focuses on challenging work．Stimulants （兴奋剂）, including caffeine, tend to make people feel as if．time is passing faster; complex jobs, like doing taxes, can seem to drag on longer than they actually do．And  emotional  events — a breakup, a promotion, a transformative trip abroad —tend to be sensed as more recent than they actually are, by months or even years．In short, some psychologists say, the findings support the philosopher Martin Heidegger' s observation that time "persists merely as a consequence of the events taking place in it．"

Now researchers are finding that the opposite thing may also be true: if very few events come to mind, then the sense of time does not persist; the brain shortens the interval that has passed．

In one classic experiment, a French explorer named Michel Siffre lived in a cave for two months, cut off from the rhythms of night and day and man-made clocks．He appeared then, convinced that he had been isolated for only 25 days．Left to its own devices, the brain tends to shorten time．

In earlier work, researchers found  that a similar case at work in people’s judgment of intervals that last only moments．Relatively infrequent stimuli, like flashes or tones, tend to increase the speed of the brain' s internal pacemaker．

On an obvious level, these kinds of findings offer an explanation for why other people' s children seem to grow up so much faster than one's own．Involved parents are all too well aware of first step in their own children; however, seeing a cousin's child once every few years, without bothering memories, shortens the time．

1.What can we infer from the first paragraph?

A．Scientists have agreed about how the brain records time．

B．Scientists all think that some cells record the intervals of time．

C．Scientists haven't agreed on how the brain records time．

D. Scientists all hold the theory that neural processes are an inside clock．

2.According．to Paragraph 3, if we have few things to do, the brain will____．

A．make the intervals of time long

B．make the intervals of time short

C．keep a state of rest

D．stop working

3.Which of the following is TRUE according to the passage?

A．Michel Siffre didn' t think he had stayed in the cave for as long as two months．

B．Parents tend to think their own children grow faster than others．

C．Michel Diffre actually stayed in the cave for twenty-five days．

D．Children usually bring bad memories to their parents．

4.In which column of a newspaper can we find this passage?

A．Social news                               B．Community activities

C．．Science                               D．Children s life

高三英语阅读理解中等难度题查看答案及解析

The best part of _____vacation isn’t going somewhere else; it’s being where you are, fully involved in _____experience.

A. /; an      B. a; the    C. the; an  D. the; /

高三英语单项填空简单题查看答案及解析

Scientists are making new studies of color and its effects on our health. They have known for a long time that the color of a room or the color of the light in it can affect our feelings and emotions. Many prisons and hospitals have at least one room that is painted pink. Officials have found that light and color can produce physical changes in our bodies.

Professor Falfan worked with a group of 9 disabled children at school in Albert. Two of the children were blind. The other seven had normal sight. The scientists changed the color of the school room, and then looked for changes in blood pressure, heart beat and breathing rate. The effects of color changes were the same for the blind children as for those with normal sight. Their blood pressure dropped from about 120 to 100. Similar changes were reported in heart-beat and the breathing. The children were also calmer and less excited. Then the colors of the room were returned to orange and white. Blood pressure, heart-beat and breathing rate went up and the children became excited again.

Professor Falfan said different colors produce different levels of light energy. He said the differences seem to affect chemicals in the brain that carry messages from nerve to nerve and from nerve to muscle.

1. Light and color can affect　　.

A. only one’s feelings and emotions

B. one’s energy

C. one’s mental changes

D. one’s heart-beat, brain activities, blood pressure, feelings and emotions

2. The color of pink had a calming effect, that is to say, the color affects　　.

A. the chemicals in the brain

B. the eyes

C. the skin

D. the muscle

3.According to the text, orange and white are colors which can make people　　.

A. calm　　B. active　　C. sick　　D. blind

13. The colors in the school room mentioned in the passage were changed from　　.

A. orange to white

B. orange to dark blue

C. orange and white to pink or some other colors

D. gray to more colors

4. After reading the passage we can conclude that　　.

A. blind people can be affected by colors, too

B. one’s heart will beat faster in a colorful room than in a white room

C. the chemicals in the brain change with feelings and emotions

D. if one’s blood pressure drops, his breathing will get slower and slower

高三英语阅读理解中等难度题查看答案及解析

Many of us have wondered what Earth is like beneath the surface. So have writers and scientists. In French novelist Jules Verne’s masterpiece Journey to the Center of the Earth, explorers go down to Earth’s center and discover amazing wonders.

But in real life, human beings haven’t even come close to the planet’s core (核心). The core is over 6,000 km down. The deepest hole ever created, according to the BBC, is the Kola Superdeep Borehole in Russia, which only goes 12.3 km down.

So how do we know about everything down below without any samples？

One good way to start is to think about the Earth’s density (密度), Simon Redfern of the University of Cambridge in the UK told the BBC.

“The density of the material on Earth’s surface is much lower than the average density of the whole Earth, so that tells us there’s something that has greater density,” Redfern said.

The challenge is to find out which heavy materials the core is made of. And the main material scientists have found is iron. The idea is that when Earth formed 4.5 billion years ago, a lot of iron made its way down to the core, taking up about 80 percent of it. Today scientists are still working on finding out which other materials the core could be made up of.

You might also wonder how we know the size of the core. There’s a one-word answer: seismology (地震学).

When an earthquake happens, seismic stations around the world record the shockwaves it sends throughout the planet. It’s like hitting one side of the planet with a huge hammer and listening on the other side for the noise.

Early research found that some shockwaves, called “S-waves”, went missing. S-waves can only travel through solid material, but not through liquid, so they must have found something molten in Earth’s center. By following the S-waves’ paths, scientists found out that rocks became liquid around 3,000 km down.

There are still many questions about the Earth’s core to answer. But the study of the dark world below isn’t just for scientists’ curiosity.

The movement of Earth’s molten iron core builds up a powerful magnetic (有磁力的) field. It protects us from radiation from the sun and is needed for compasses and GPS systems to work.

So perhaps none of us will ever set eyes on the core, but it’s good to know it’s there.

1.The author mentions Jules Verne’s novel Journey to the Center of the Earth in the first paragraph to　　　　　　　　 .

A. discuss the possibility of going down to Earth’s center

B. show how much humans have discovered about Earth

C. paint a picture in our imagination of the dark world below

D. show humans’ deep interest in Earth’s center

2.We can learn from the article that “S-waves”　　　　　　　　　　　　 .

A. are often used to predict earthquakes

B. cannot travel through liquid material

C. are the most noticeable shockwaves produced by earthquakes

D. can travel most rapidly at 3,000 kilometers below Earth’s surface

3.We can infer from the last three paragraphs that 　　　　　　　　　　　 .

A. research into Earth’s core has hardly made any progress in recent years

B. improvements in GPS systems could help people find out more about Earth

C. Earth’s core helps to protect humans from harm

D. scientists are likely to reach Earth’s center within dozens of years

高三英语阅读理解中等难度题查看答案及解析

Health and climate scientists have mapped how climate change affects different parts of the world in different ways. The scientists point to the fact that changes in the past thirty years may, have been affecting human health. Possible effects include more deaths from extreme(极度的) heat or cold, more storms and more crop failures in dry periods.

The health and climate scientists recently estimated(估计) that climate changes caused by human activity lead to more than one hundred and fifty thousand deaths each year. Cases of sickness are estimated at five million. And the W.H.O. says the numbers could rise quickly by the year of 2003.

Jonathan Patz of an environmental institute led the study. Professor Patz points out that climate scientists connected global warming with the heat that killed thousands in Europe in August, 2003. But he says poor countries least responsible(对……负责) for the warming are most in danger from the health effects of higher temperatures.

Professor Patz says areas in greatest danger include southern and eastern Africa and coastlines along the Pacific and Indian oceans. Also, large cities experience what scientists call a "heat island"effect that can make conditions worse.

Representatives(代表) from about two hundred countries hold a meeting in Canada, to discuss climate change. The ten-day meeting ends on December 9th. It is the first such United Nations meeting since the Kyoto Protocol(京都议定书) took effect earlier this year. The agreement aims to reduce the amount of carbon dioxide(二氧化碳) and other heat-trapping(吸热的) gases sent off into the air.

1.Who is Jonathan Patz?

2.Which of the following statements is TRUE according to the passage?

3.Possible effects from the climate changes include the following EXCEPT ______.

4.According to the health and climate scientists, climate changes have been caused by ______.

5.We can infer from the passage that ______.

高三英语阅读理解中等难度题查看答案及解析