Gray hair is simply a part of the normal aging process, and the rate you go silver is genetically predetermined. Going gray is not associated with earlier death, and premature graying is not, generally speaking, a sign of an illness or ill health in younger adults. There are, however, some specific health conditions associated with gray or white hair, but for most of us, going gray is just a fact of life.
Hair color comes from the pigment melanin(黑色素), which determines your individual shade. Hair without any melanin is pure white. The pigment is produced in cells called melanocytes, which inject pigment into the hair. At some point in everyone's lifetime, these cells slow down and eventually stop producing color. Scientists have yet to identify the exact mechanism by which melanocyte cell death occurs.
A study of more than 4,000 women and men from 20 countries determined that about 75% of people between the ages of 45 and 65 have some gray hair. In general, people of European descent gray earliest followed by Asians and Africans. It's interesting to note that a lucky 1 in 10 has no gray hair by retirement age. Beginning at age 30, your chances of having gray hair go up 10-20% per decade.
It may feel like you have more grays after a stressful event, but that's probably because middle age is basically a series of anxiety-ridden events. Between working, raising kids, and caring for older parents, the "sandwich" years of 45-65 can be stressful, especially for women. They are also when we naturally start to look older.
At this point, there is still no silver bullet to keep away the grays.
【小題1】What would be the best title for this passage?

A．Going gray. B．Tips to make hair color last
C．Why does hair turn gray? D．Gray hair is in fashion.
【小題2】Which of the following is a true statement according to the passage?
A．Scientists have found out how to prevent hair from turning gray.
B．Europeans are more likely to gray than Asians and Africans.
C．Gray hair means poor health or a sign of illness.
D．Everyone will inevitably get gray hair by retirement age.
【小題3】Which is not among the reasons for hair turning gray according to the passage?
A．Being physically weak. B．Stress from different sides.
C．Death of melanocyte cell. D．Genetic factors.
【小題4】What does “silver bullet” in the last paragraph probably mean?
A．Make-up B．Scientific research. C．Chemical weapon. D．Cure.


【小題1】C
【小題2】B
【小題3】A
【小題4】D

解析試題分析：本文介紹了為什么人的頭發(fā)會(huì)變白。這是自然老化的過(guò)程、與基因有關(guān)，還和黑色素的分泌的多少有關(guān)，黑色素越少，頭發(fā)越白。通過(guò)研究20多個(gè)國(guó)家的4000多男性和女性可知，有年齡原因也有地域原因。生活壓力大也是原因之一。
【小題1】主題歸納題。根據(jù)全文尤其是文章的第一句話判斷，文章是在講頭發(fā)變白的應(yīng)用。所以選C。
【小題2】推理判斷題。根據(jù)第三段的In general, people of European descent gray earliest followed by Asians and Africans.可知：歐洲人早于亞洲人和非洲人頭發(fā)變花白。B
【小題3】細(xì)節(jié)理解題。根據(jù)第一段的內(nèi)容可知，銀發(fā)是一個(gè)正常老化的過(guò)程，頭發(fā)變白由基因已經(jīng)決定了的。與早亡無(wú)關(guān)，少白頭也不是生病或者身體不舒服的標(biāo)志。所以選A（身體虛弱）。
【小題4】詞義推測(cè)題。根據(jù)最后一段的意思可知：人在45-65之間壓力很大，尤其是婦女，還有自然的老化問(wèn)題。所以選D（治愈）。其他選項(xiàng)的意思是：Make-up化妝；Scientific research.科學(xué)研究；Chemical weapon.化學(xué)武器。
考點(diǎn)：科普類閱讀。

練習(xí)冊(cè)系列答案
相關(guān)習(xí)題

科目：高中英語(yǔ) 來(lái)源： 題型：閱讀理解

Of all the animals in the animal kingdom, which one (aside from man) is the cleverest?
There are several ways of measuring the intelligence of animals. In one test a scientist sets three same cans on a table. While the animal watches, he puts food under one of the cans. Then he leads the animal away. Some time later, he brings it back to see if it remembers which can has the food. No smelling is allowed; the animal must go directly to the correct can or it fails.
This is called a delayed-response test. The idea is to find out how long an animal’s memory can keep information. The scientists would try showing the cans to the animal one hour later, or two hours later, or even a full day later. They discovered that chimpanzees and elephants have the best memory, and were able to remember the correct can for at least twenty hours. No other animal is close. Dogs came next, but they only remember for nine hours.
To settle the matter, the scientists designed a huge maze (迷宮) and ran the chimps and elephants through it. The maze was very difficult, with many blind paths and dead ends. It took the chimps ten minutes to find their way out. The elephants needed half an hour. Even allowing for the elephants’ slower rate of speed, the test shows that chimpanzees are the cleverest animals.
From this and other tests, the scientists drew the following conclusion: an animal’s intelligence depends on the size of its brain in proportion (比例) to the size of its body. The elephant’s brain weighs ten pounds. But this is only 1/600th of its 6,000 pounds body. A chimp’s brain weighs about one pound, or 1/120th of its total body weight. So in proportion to its body size, the chimp has four times as much brain as the elephant----more brain for less body. The chimp is the champ!
【小題1】Which is the best title?

A．The Elephant’s Memory B．The Cleverest Animal
C．Judging Intelligence D．The Chimp’s Brain
【小題2】The main idea of this passage is that _____.
A．there are several ways of measuring the intelligence of animals
B．chimps and elephants have the best memory
C．intelligence tests show that the chimp is the cleverest animal
D．the scientists designed a huge maze and ran the chimps and elephants through it
【小題3】 The delayed-response test is designed to test an animal’s _____.
A．eyesight B．intelligence C．learning ability D．memory
【小題4】The passage tells that elephants _____.
A．never forget things B．a(chǎn)re more clever than chimps
C．a(chǎn)re slower-moving than chimps D．have better memories than chimps
【小題5】According to the passage, a rhinoceros (犀牛) that weighs 2100 pounds, and has a 3-pound brain is _____.
A．a(chǎn)s clever as a chimp B．more clever than an elephant
C．less clever than an elephant D．a(chǎn)s clever as an elephant

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源： 題型：閱讀理解

Researchers found that people become happier and experience less worry after they reach the age of fifty. In fact, they say by the age of eighty-five, people are happier with their life than they were when they were eighteen years old.
The findings came from a survey of more than three hundred forty thousand adults in the United States. The Gallup Organization questioned them by telephone in two thousand eight. At that time, the people were between the ages of eighteen and eighty-five.
The researchers asked questions about emotions like happiness, sadness and worry. They also asked about mental or emotional stress.
Arthur Stone in the Department of Psychiatry and Behavioral Science at Stony Brook University in New York led the study. His team found that levels of stress were highest among adults between the ages of twenty-two and twenty-five.
The findings showed that stress levels dropped sharply after people reached their fifties.
Happiness was highest among the youngest adults and those in their early seventies. The people least likely to report feeling negative emotions were those in their seventies and eighties.
The findings appeared in the Proceedings of the National Academy of Sciences.
Researchers say they do not know why happiness increases as people get older. One theory is that, as people grow older, they grow more thankful for what they have and have better control of their emotions. They also spend less time thinking about bad experiences.
Professor Stone says the emotional patterns could be linked to changes in how people see the world, or maybe even changes in brain chemistry.
The researchers also considered possible influences like having young children, being unemployed or being single. But they found that influences like these did not affect the levels of happiness and well-being related to age.
The study also showed that men and women have similar emotional patterns as they grow older. However, women at all ages reported more sadness, stress and worry than men.
【小題1】What is the best title of the passage?

A．The older a person is, the happier he grows. 
B．The more lighthearted a person is, the happier he is. 
C．The older a person is, the more clever he grows. 
D．The older a person is, the more stressed he feels. 
【小題2】 We can learn from the research that _________.
A．only when people get older, will they feel happier 
B．older people usually have no worries in their life 
C．older people are more likely to be thankful in life 
D．stress levels among the youngest are the highest of all 
【小題3】According to the researchers, what is probably the reason why people grow happier when they get older?
A．When people get older, they can’t remember bad experiences. 
B．When people get older, they have no young children to care about. 
C．When people get older, they don’t care about their feelings. 
D．When people get older, they learn to adjust their feelings. 
【小題4】 What would the writer probably deal with in next paragraph?
A．Advice to the young people on how to keep happy. 
B．Why women at all ages are more sad, stressed and worried. 
C．Advice to the old people on how to live longer. 
D．Why people will grow happier with their ages. 
【小題5】 What do you think the Proceedings of the National Academy of Sciences is?
A．A Gallup organization. B．A university in New York. 
C．A popular science magazine. D．A research institution 

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源： 題型：閱讀理解

Fear may be felt in the heart as well as in the head, according to a study that has found a link between the cycles of a beating heart and the chance of someone feeling fear.
Tests on healthy volunteers found that they were more likely to feel a sense of fear at the moment when their hearts are contracting (收縮) and pumping blood around their bodies, compared with the point when the heartbeat is relaxed. Scientists say the results suggest that the heart is able to influence how the brain responds to a fearful event, depending on which point it is at in its regular cycle of contraction and relaxation.
Sarah Garfinkel at the Brighton and Sussex Medical School said: "Our study shows for the first time that the way in which we deal with fear is different depending on when we see fearful pictures in relation to our heart."
The study tested 20 healthy volunteers on their reactions（反應(yīng)）to fear as they were shown pictures of fearful faces. Dr Garfinkel said, "The study showed that fearful faces are better noticed when the heart is pumping than when it is relaxed. Thus our hearts can also affect what we see and what we don't see - and guide whether we see fear."
To further understand this relationship, the scientists also used a brain scanner (掃描儀) to show how the brain influences the way the heart changes a person's feeling of fear.
"We have found an important mechanism by which the heart and brain ‘speak’ to each other to change our feelings and reduce fear," Dr Garfinkel said.
"We hope that by increasing our understanding about how fear is dealt with and ways that it could be reduced, we may be able to develop more successful treatments for anxiety disorders, and also for those who may be suffering from serious stress disorder."
【小題1】What is the finding of the study?

A．One's heart affects how he feels fear.
B．Fear is a result of one's relaxed heartbeat.
C．Fear has something to do with one's health.
D．One’s fast heartbeats are likely to cause fear.
【小題2】The study was carried out by analyzing _______.
A．volunteers' heartbeats when they saw terrible pictures
B．the time volunteers saw fearful pictures and their health conditions
C．volunteers' reactions to horrible pictures and data from their brain scans
D．different pictures shown to volunteers and their heart-brain communication
【小題3】Which of the following is closest in meaning to "mechanism" in Paragraph 6?
A．Order. B．System. C．Machine. D．Treatment.
【小題4】This study may lead to _______.
A．treating anxiety and stress better
B．explaining the cycle of fear and anxiety
C．finding the key to the heart-brain communication
D．understanding different fears in our hearts and heads

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源： 題型：閱讀理解

Sooner or later, many families will face the situation of moving. The experience can be very bad for kids, who may not be a part of the decision to move and may not understand it. You can take steps to make the entire process (過(guò)程) easier for everyone.
Many kids like to stay in familiar places. So as you consider a move, weigh the benefits (好處) of that change against the comfort that neighborhood, school, and social life give your kids. If your family has recently dealt with a big life change, such as death, you may want to put off a move to give your children time to accept the fact.
The decision to move may be out of your hands, perhaps because of a new job or money problems. Even if you’re not happy about the move, try to keep a positive (積極的)attitude to it. During the move, a parent’s attitude can greatly influence kids.
No matter what the results are, the most important way to prepare kids to move is to talk about it. Try to give your children as much information about the move as possible. You can ask kids to join in the planning such as house-hunting or the search for a new school. This can make the change feel less like it’s being forced on them. If you’re moving across town, try to take your children to visit the new house and the new neighborhood.
A move can have many problems, but good things also come from this kind of change. Your family might grow closer and you may learn more about each other by going through it together.
【小題1】According to the text, a move can be a bad experience for kids because ______.

A．they may feel they’re forced to do so
B．they often feel lonely in a new school
C．they are ignored by their busy parents
D．they are tired of the moving process
【小題2】Which is the most important when making the move easier for children?
A．Allowing them to choose a school by themselves.
B．Trying not to show them the bad parts of a move.
C．Offering them as much information as possible.
D．Promising to choose a new house with them.
【小題3】The author wrote this text mainly to tell us ______.
A．what we should do before a move
B．how to prepare children for a move
C．how a move can change the family
D．why parents should talk to children often.

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源： 題型：閱讀理解

The first newspaper was written by hand and put up on walls in public places. The earliest daily newspaper was started in Rome in 59 BC. In the 700s the world’s first printed newspaper was published. Europe didn’t have a regularly printed newspaper until 1609, when one was started in Germany.
The first regularly published newspaper in English was printed in Amsterdam in 1620. In 1621, an English newspaper was started in London and was published once a week. The first daily English newspaper was the Daily Courant, which came out in March 1702.
In 1690, Benjamin Harris printed the first American newspaper in Boston .But not long after it was first published, the government stopped the paper. In 1704, John Campbell started the Boston Newspaper, the first newspaper published daily in the American colonies（殖民地）. By 1760, the colonies had more than thirty daily newspapers.There are now about 1, 800 daily papers in the United States.
Today, as a group, newspapers in English have the largest circulation (發(fā)行量)in the world .But the largest circulation for a newspaper is that of the Japanese newspaper Asahi Shimbun . It sells more than eleven million copies every year.
【小題1】The first regularly printed European newspaper started in ________.

A．Rome in 59 BC B．Germany in 1609 
C．Amsterdam in 1620 D．England in 1621 
【小題2】The first daily newspaper in English started in _________.
A．1620 B．1621 C．1590 D．1702 
【小題3】What does the author want to inform us?
A．History of newspapers 
B．History of daily newspapers 
C．The beginning of newspapers 
D．On reading newspapers 

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源： 題型：閱讀理解

Below is a discussion on a website.

http://www.TalkingPoints.com/
Stuck on a desert island?
Started on 23rd April by Steve Posts 1 – 7 of 42
Post 1
Steve
USA
Hi, everyone. What would you miss most and least if you were stuck on a desert island? For me, it would be the changing seasons in New England. I guess this will sound stupid but I’d probably miss the rain, too. I wouldn’t miss getting up at six every day to go to work, though! What about you?
Post 2
Tomas
Germany
Good question. Steve, I think I’d miss different types of bread, and shopping at the supermarket. I’d miss the food most. What would I miss least? My mobile phone---I’d like to be completely quiet --- at least for a little while
Post 3
Paola
Italy
I would miss the company of people because I know I’d like to have someone to share experiences with. I’d go mad on my own. And I sure wouldn’t miss junk mail(垃圾郵件) --- I hate coming home every evening and a pile of junk mail in my post box.
Post 4
Miko
Japan
Hi, I would miss Manga cartoon, the Internet and Japanese food, like sushi. I’d also miss TV shows and shopping for clothes…
Post 5
Roger
UK
I would miss my daily newspaper and listening to the news on TV and radio. I’d feel very cut off if I didn’t know what was happening in the world. What I’d miss least would be traffic jams in the city, particularly my journey to work.
Past 6
Jayne
Why hasn’t anyone mentioned their family? I’d be lost without my husband and two kids. They’re the most important for me. And I can’t get started in the morning without a cup of black coffee. I wouldn’t miss doing the housework!
Post 7
Jaime
Mexico
It would have to be music. I couldn’t live without my music. I wouldn’t miss going to school at all or doing homework!
【小題1】 Who would miss his or her family most?
A．Jaime B．Jayne C．Miko D．Paola.
【小題2】Which of the following people would feel most uncomfortable without the news media?
A．Steve. B．Jaime C．Roger. D．Tomas
【小題3】How many of them mentioned that they would miss food or drink?
A．One B．Two C．Three D．Four

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源： 題型：閱讀理解

Can we give a hand to those endangered animals? Yes, we may only do a little bit, but together our small actions add up to a lot.
1. Protect wildlife habitat.
Perhaps the greatest threat that faces many species is the widespread destruction of habitat. Cutting down forests, farming, and development all result in loss of wildlife habitat. In areas where rare species live, habitat destruction can quickly force a species to extinction. By protecting habitat, entire communities of animals can be protected together naturally. Parks and reserves are now all too often the only habitats that are left untouched by habitat destruction.
2. Reduce the threat of invasive (入侵的) species.
The spread of non-native species has greatly reduced native populations around the world. Invasive species compete with native species for resources (資源) and habitat. They can even prey on native species directly, forcing native species towards extinction.
3. Place decals (貼花紙) on windows.
It is reported that as many as one billion birds in the United States die each year because of collisions (碰撞) with windows. You can help reduce the number of collisions simply by placing decals on the windows in your home and office.
4. Slow down when driving.
Many native animals have to live in developed areas and this means they must move in human-living areas. One of the biggest obstacles (障礙) to them is that created by roads. Roads divide habitat and present a constant risk to any animal attempting to cross from one side to the other. So when you’re out and about, slow down and keep an eye out for wildlife.
【小題1】 What would be the best title for this passage?

A．How animals go to extinction
B．The importance of protecting wildlife
C．What to do to help save wildlife
D．How to protect wildlife habitat
【小題2】By writing the underlined sentence, the writer means that _____.
A．more parks and reserves should be built
B．we should have more habitats free of destruction
C．there is a need for improvement in parks and re-serves
D．parks and reserves are good examples of protecting wildlife
【小題3】People are advised to put decals on windows to _____.
A．decorate the houses and beautify the environment
B．protect the windows from birds hitting
C．a(chǎn)ttract more birds to make homes nearby
D．a(chǎn)void birds hitting the windows by mistake
【小題4】The underlined phrase “prey on” in the passage means _____.
A．drive awayB．live withC．kill for foodD．fight with

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源： 題型：閱讀理解

Hospital emergency rooms treat injured fingers all the time. Without treatment, a bad cut can lead to permanent damage. But how should a person know when a bleeding cut is serious enough to require medical attention? We asked Dr Martin Brown, chairman of the department of emergency medicine at Inova Alexandria Hospital in Virginia.
First, the medical term for a cut or tear in the skin is a laceration(嚴(yán)重劃破，撕裂傷). Dr Brown says the length is usually not as important as the depth. He says a long cut on a finger can likely be treated without a visit to a doctor if the wound is not very deep. “If you have a short but deep laceration where there’s been a structure underneath that’s been damaged － a tendon, a nerve, a blood vessel,” says Martin, “it may, in fact, need professional attention.”
Some injuries － like a fingertip that gets cut off － might even require surgery to repair. That requires a specialist to either file(銼平) down the bone or reattach the fingertip. More often, filing down the bone is what is done because reattaching a fingertip is often not successful.
How a wound bleeds can be a sign of how serious it is. Minor cuts usually produce what is known as venous (靜脈) bleeding. This means the blood flows steadily from the injury. The bleeding will often stop when pressure is put on the wound. Dr Brown says in most cases holding direct pressure with clean gauze or a cloth for four to five minutes should stop the bleeding. With a cut finger, holding the hand above the heart can reduce the loss of blood. But if a cut appears to be pumping blood out with some force, this may be a sign of arterial(動(dòng)脈) bleeding. This kind of injury should be treated by a medical professional as soon as possible.
Even a cut that does not require medical attention must be kept clean to prevent infection. Small cuts should be cleaned gently with clean water. Use a washcloth to clean the area if the wound is dirty. Dr Brown says cuts should be covered with a clean, dry bandage.
【小題1】What does the writer want to tell the readers in the first paragraph?

A．Hospital emergency rooms always treat injured fingers. 
B．A bleeding cut is serious enough to require medical attention 
C．Dr Martin Brown is in charge of Inova Alexandria Hospital. 
D．It is important for us to be able to tell how serious a finger cut is. 
【小題2】According to the passage,         .
A．a(chǎn) finger cut without treatment can lead to permanent damage 
B．the length of a cut on a finger is more important than the depth 
C．a(chǎn) long but not very deep cut often doesn’t need professional attention 
D．a(chǎn) short but deep laceration that has been damaged need professional attention. 
【小題3】The underlined word “reattach” in Para.3 is closest in meaning to         .
A．repair B．rebuild C．reconstruct D．reconnect 
【小題4】Which of the following statements is NOT true according to the passage?
A .How a wound bleeds can show us how serious the wound could be.
B Venous bleeding will often stop when we put pressure on the wound.
C. Holding up the hand with a finger cut can reduce the loss of blood.
D. Arterial bleeding should get professional treatment as soon as possible
【小題5】.The best title of this passage should be         .
A．Hospital Emergency Treatments For Injured Fingers 
B．When a Cut Finger Is More Serious Than It Might Seem 
C．Serious Finger Cut That Requires Medical Attention 
D．Keep Finger Cuts Clean to Prevent Serious Infection 

查看答案和解析>>

同步練習(xí)冊(cè)答案