Now, we know that if we do not get enough vitamins, we are at risk of developing a number of diseases. As a result, vitamin supplements（补品），though expensive, are popular with people who worry that they are not getting enough vitamins from the foods they eat. But contrary to what many people think, medical experts have found little evidence that most supplements do anything to improve health or protect against disease.
In fact, medical experts warn that taking too many of some vitamins can be harmful. For example, too much vitamin E can cause bleeding. People should discuss what vitamins they take with their doctors, as some vitamins can produce harmful side effects when mixed with medicines.
Experts, however, do say that sometimes vitamins can help prevent disease. People who know they lack a particular vitamin should take vitamin supplements. Some older adults, for example, may not have enough vitamin B-twelve. This is because, as people get older, their body loses its ability to take it from foods. Also, people who spend much time inside may need some extra vitamin D as the skin makes this vitamin from sunlight.
Different vitamins are found in different foods. Vitamin A is found in fish liver oil. It also is in the yellow part of eggs. Sweet potatoes, carrots and other darkly colored fruits and vegetables contain substances that the body can change into vitamin A. Vitamin B-twelve is found in green leafy vegetables and other foods, like fruits. Vitamin K can be found in pork products.
In fact, for most people, a balanced diet can ensure enough of the vitamins our bodies need. So, it is important for us to eat a mixture of foods every day to ensure that we get enough vitamins our bodies need. Vitamin supplements are popular with people because ________.
| A．people mistakenly think that they are good for their health |
| B．they contain more vitamins than the foods people eat |
| C．food does not provide enough vitamins people need |
| D．people fear that a lack of vitamins will lead to disease |
From the passage, we can learn that medical experts advise people _________.
| A．never to take any vitamin supplements |
| B．to depend only on food for their vitamins |
| C．not to take any vitamins together with medicines |
| D．to consult doctors before taking vitamin supplements |
For people who lack Vitamin B-twelve, they can eat more from _______.
A. sweet potatoes B. pork products C. green leafy vegetables D. eggs
42. What would be the best title of the passage?
A. Getting enough vitamins through a balanced diet.
B. Vitamin supplements do harm to our health.
C. Vitamins are important to our health.
D. Lacking vitamins can cause many diseases.
Do other countries’ students also have so much homework? What do they usually do in their free time? You may feel curious about them.
On April 8, a report came out on the lives of high school students in China, Japan, South Korea and the US. It surveyed around 6,200 students from the four countries last year. You will find the answers to many of your questions in this report.
Who studies hardest?
Chinese students spend the most time studying. Nearly half of Chinese students spend more than two hours on their homework every day. That’s much more than students of the US (26.4%), Japan (8.2%) and South Korea (5.2%).
Who sleeps most often in class?
Japanese students fall asleep in class most often. About 45% of them said they sometimes doze offin class. In South Korea, it’s 32%; in the US, 21%; and 5% in China.
South Korean students don’t like taking notes. About 70% said they write down what the teacher says in class, many fewer than in Japan (93%), China (90%) and the US (89%).
Who is the most distracted (分心的)?
American students are the most active in class, but also the most distracted: 64.2% said they chat with friends in class; 46.9% said they eat snacks in class; and 38.9% said they send e-mails or read unrelated books in class.
What do they do after school?
In their spare time, most Chinese students study or surf the Internet. Most American students hang out with their friends. Most Japanese students do physical exercise. Most Korean students watch TV.The report is about ___________.
| A．the countries | B．the subjects | C．the students’ lives | D．the high schools |
What country isn’t mentioned in the report?
| A．The US | B．South Korea | C．Japan | D．India |
__________ of the Chinese students spend more than two hours on their homework.
| A．26.4% | B．8.2% | C．5.2% | D．48.6% |
The phrase doze off means ___________.
| A．be half asleep | B．get up | C．eat snacks | D．send emails |
Once in a village, the villagers built a new church building and people came from far and wide to see it. They admired its beauty! They said it was the most beautiful building in the world. Up on the roof, a little nail（钉子）heard the people praising everything about the lovely structure – except the nail! No one even knew he was there, and he became very angry and sad.
“If I am not important, nobody will miss me if I quit!” So the nail then released (松开) its hold, got down from the roof, and fell into the mud.
That night it rained and rained. Soon, the board that had no nail was blown away, and the roof began to leak (漏水). The water flowed down along the walls and over the beautiful pictures on the walls. The plaster (石膏) began to fall, the floor was ruined, and the Bible was also ruined by water. All this was because a little nail decided to quit!
But what of the nail? While holding the board, it was not known by others but it was useful. Buried in the mud now, it was useless and would soon be eaten up by rust!
What the story wants to say is that every member is important to a whole group!
You may, like the nail, feel not important at times, but just like the nail, your absence is felt. A big building might fall to pieces. You are important to a group even if you are small.Why did the nail decide to quit?
| A．Because he was not able to hold on any longer. |
| B．Because he was angry and sad without people’s praising him. |
| C．Because he knew a big nail would replace him. |
| D．Because he had finished his task successfully. |
What’s the result of the nail’s giving up?
| A．People began to realize the importance of the nail. |
| B．The nail was put in a more important position. |
| C．Many things in the building were ruined and the nail was eaten up by rust. |
| D．The nail regretted his original decision at last. |
The passage wants to tell us that ______.
| A．no matter how small you seem, you are important to a group |
| B．it is a pity that small people are never looked up to |
| C．quit when it is necessary, and don’t care about what others say |
| D．being valued is important to a man |
Can you remember a morning when you’ve woken up to the ring of your alarm clock and wished you could stay in bed? You haven’t slept well, your hair is a mess. Worse, you can’t stop yawning. Yawning is universal to humans and many animals. Cats, dogs and fish yawn just like humans do! Yawning is an involuntary(无意识的,不自觉的) action during which you open your mouth and breathe deeply. The average duration of a yawn is about 6 seconds.
The purpose and cause of yawning are still a mystery. Scientists are not sure what causes a yawn. People yawn when they are tired or bored, but they also yawn when they aren’t. There are many ideas explaining why we yawn.
One idea is that yawning is a way for the body to become more alert by taking in more oxygen. A yawn increases the heart rate, forces carbon dioxide out of the lungs and blood stream, and brings oxygen to the brain. But one study showed that volunteers given a lot of oxygen did not yawn any less than before, while those given a lot of carbon dioxide did not yawn more.
Another idea is that early humans used yawning as a form of communication. If one decided it was time to sleep, they would tell the others by yawning and they would do it in return to show they agreed.
A third explanation comes from psychology professor Gordon Gallup of University at Albany in New York. He said that as people yawn, they cool off their brains. “Brains are like computers.” he said. “They only operate efficiently and effectively when they’re cool. Many things connected to yawning, like being tired, make the brain hot, and yawning can reduce the heat.”
Scientists have sent people into space, and created terrible nuclear weapons, but there are lots of seemingly simple things, such as why we yawn, or hiccup（打嗝）, that they can’t figure out. Next time you are in class in the morning, let out a big yawn and watch to see how many of your classmates yawn in response!What’s the purpose of the description of how bad you may feel when you’re woken up in the morning?
| A．To explain why humans yawn. |
| B．To explain how humans start yawning. |
| C．To lead into the topic of yawning. |
| D．To complain about being woken up by the clock. |
Which is not among the possible reasons for yawning mentioned in the passage?
| A．A way to show that you feel hot. |
| B．A way to get rid of carbon dioxide. |
| C．A way to cool off your brain. |
| D．A way to communicate. |
In which situation are you likely to yawn?
| A．When you feel frustrated. |
| B．The weather is hot. |
| C．Someone else yawns near you. |
| D．When you breathe in a lot of carbon dioxide. |
What can we learn from the passage?
| A．The real reason why humans and most animals yawn. |
| B．Hiccups are an involuntary human action similar to yawns. |
| C．The more an action can be studied, the easier it is to research. |
| D．Finding out why humans yawn should be easier than sending people into space. |
Every family with kids has seen its share of arguments, shouting and complaining. It turns out that all those conflicts serve an important purpose in the development of children . Saying “no” followed by a bad temper, just may be an unavoidable part of growing up. And that’s a good thing. These are the first steps toward independence. Even young children have to challenge their parents sometimes. Studies have shown the following:
·Although stressful, conflicts are beneficial for children.
·Learning to manage conflicts is necessary for a child’s development.
·Conflicts during the preschool years occur because children desire more attention than parents can or should give.
If you understand why conflicts occur, it can minimize the conflicts between you and your children. Conflict is a child’s attempt to develop a sense of self and how he or she learns to express his or her needs and ideas. Parents develop and drive this independence by putting children to the outside world both formally and informally.
Conflicts can grow out of a difference of opinion or might just be a way to blow off steam(发脾气). In rare situations, constant conflicts between parents and children can indicate a deeper emotional problem. Consult your doctor if this seems to be your situation.
It’s important to offer your child choices, which should be determined by age and developmental level. The more responsible a child is, the more choices he or she gets in reward. You can threaten your child with punishment, but often offering a choice will better improve angry situations. Consequences and rewards should have some meaning to your child.
Often a child’s adverse(敌对的)reaction when he or she hears the word “no” can be avoided by giving the child an explanation as to why you have refused his or her request.The intended readers of this passage are .
| A．parents | B．doctors | C．teachers | D．children |
By saying "that's a good thing" in Paragraph 1, the author means .
| A．children behave politely |
| B．children try being independent |
| C．parents control their feelings well |
| D．parents understand their children |
If a 3-year-old boy challenges his parents angrily, according to studies, he may .
| A．feel being overlooked by his parents. |
| B．get tired of being looked after by his parents. |
| C．want to stay with his parents at any time. |
| D．be blamed by his parents for his faults. |
In most cases ,the conflicts between parents and their children .
| A．lead to more misunderstandings |
| B．doesn't really mean a deep emotional problem |
| C．is an important choice |
| D．involve visiting doctors |
What can be concluded from the passage?
| A．Children understand what their parents think of clearly. |
| B．Children enjoy giving their opinions by conflicting with their parents. |
| C．Most parents would rather punish their children than reward them. |
| D．Communication can reduce conflicts between parents and children. |
Animals can move from place to place, but plants cannot. When an animal is under attack, it can run away or fight back. Plants certainly cannot run away, and they lack teeth and claws. But plants can defend themselves by using both physical and chemical means.
Some plants have their own ways to keep animals away. For example, the leaves of the holly plant have sharp spines(刺) that discourage grass-eating animals. Holly leaves on lower branches have more spines than leaves on upper branches. This is because the lower leaves are easier for most animals to reach.
Some plants , such as the oak trees, have thick and hard leaves that are difficult for animals to eat. Some grasses may contain a sandy material; eating such grasses wears down the animal’s teeth.
Many plants also have chemical defenses. Some plants produce chemicals that taste bitter or cause an unpleasant reaction. Some plants may fight against an attack by increasing the production of these chemicals. When a caterpillar(毛虫)bites a tobacco leaf, the leaf produces a chemical messenger. This messenger sends to the roots the information to produce more nicotine. The higher levels of nicotine discourage the caterpillar.
Many plants depends on both physical and chemical defenses. A certain plant in China , for instance, has prickly(多刺的) leaves, and each prickle contains poisonous venom(毒液). A single experience with this kind of plant will teach an animal to stay away from it in the future.The holly plant has more spines on the lower leaves because most animals .
| A．can get the lower leaves easily | B．like eating the lower leaves |
| C．like leaves with sharp spines | D．have teeth and claws |
To defend themselves , oak trees use .
| A．chemical means | B．physical means |
| C．bitter chemicals | D．sandy materials |
How does tobacco protect itself against an attack from a caterpillar?
| A．Its leaves fight against the attack by physical means. |
| B．Its roots send a messenger to discourage the caterpillar. |
| C．Its roots increase the production of nicotine when it is attacked. |
| D．Its leaves produce poisonous sand to drive the caterpillar away. |
What would be the best title for this passage?
| A．Plants and Animals | B．How Plants Defend Themselves |
| C．Attacks and Defenses | D．How Animals Eat Plant Leaves |