As warming continues, scientists warn the oxygen content of oceans across the planet could be more and more reduced, with serious consequences for the future of fish and other sea life.
1.One is the simple fact that as water gets warmer, it can hold less dissolved (溶解的) oxygen. The other reason is less obvious. The entire ocean gets its oxygen from the surface — either from the atmosphere, or from photosynthesizing algae floating at the top of the sea. 2.
Global warming is expected to reduce the mixing of the ocean by making surface seawater lighter. That’s because in a warmer world we can expect more rainfall and more melting(融化) of glaciers, icebergs, and ice sheets. 3.The extra heat from the warming atmosphere will also make surface water expand and thus make it lighter still. 4.Instead, more of the oxygen will remain near the surface, where it will be used up by oxygen-breathing organisms.
A low-oxygen ocean may become an inescapable feature of our planet. A team of Danish researchers wondered how long oxygen levels would drop if we could somehow reduce our carbon dioxide emissions to zero by 2100. They determined that over the next few thousand years oxygen levels would continue to fall, until they declined by 30 percent. The oxygen would slowly return to the oceans, but even 100,000 years from now they will not have fully recovered. 5.
A. It’s not known why the oxygen level of oceans has reduced.
B. Scientists point to two reasons to expect a drop in ocean oxygen.
C. Fresh water’s inpouring will make the water at the ocean’s surface lighter.
D. The oxygen then spreads to the deep ocean as the surface water slowly sinks.
E. Global warming has caused the reduction of the oxygen content of oceans worldwide.
F. The light surface water will be less likely to sink so the deep ocean will get less oxygen.
G. If they are right, we have every reason to worry about the major effect it has on sea life.
Ed Viesturs grew up in Rockford, Illinois, where the tallest thing on the horizon was the water tower. But on Thursday, Viesturs became the only American to climb to the top of the world's 14 highest mountains.
His last hike was up Mount Annapurna, in Asia's snowcapped Himalayas. At 26,545 feet, its peak is the 10th highest in the world. It is the mountain that inspired him to start climbing.
"It tends to be the trickiest, the most dangerous," said Viesturs. "There's no simple way to climb it. There are threatening avalanches (雪崩) and ice falls that protect the mountain."
In high school, Viesturs read French climber Maurice Herzog's tale of climbing the icy Annapurna. Herzog's story was of frostbite (冻伤) and difficulty and near-death experiences. Viesturs washookedright away.
Viesturs got his start on Washington's Mount Rainier in 1977, guiding hikes in the summer. Fifteen years ago, he set out to walk up to the world's highest peaks. Finally, he's done.
The pioneering climber talks about mountains as if they were living creatures that should be treated with respect. "You have to use all of your senses, all of your abilities to see if the mountain will let you climb it," said Viesturs. "If we have the patience and the respect, and if we're here at the right time, under the right circumstances, they allow us to go up, and allow us to come down."
What's next for a man who can't stop climbing? "I'm going to hug my wife and kids and kind of kick back and enjoy the summer," says Viesturs. But for a man who's climbed the world's 14 tallest mountains, he will probably soon set off on yet another adventure.
1.What record has Ed Viesturs set?
A. He has succeeded in climbing to the world’s 14th highest mountain.
B. He has been to the top of the world’s 14 highest mountains.
C. He has become the first to climb to the height of 26,545feet.
D. He has become the first man to climb to the top of 14 highest mountains in the world.
2.The underlined word “hooked” in Paragraph 4 can be replaced by “______”.
A. frightened B. discouraged C. interested D. upset
3.The author used Viestures’ words in Paragraph 6 to support a view that ______.
A. mountain climbing is a dangerous sport
B. mountains should be regarded as living creatures
C. mountain climbing needs more skills than physical energy
D. those who like mountain climbing won’t stop climbing
4.What’s the next probably plan of Viestures?
A. Stopping climbing and staying with his family.
B. Climbing to the top of the world’s 14 tallest mountains again.
C. Climbing another one of the highest mountains.
D. Writing down the experiences about his adventure.
Are you preparing for a big test? If so, you may want to go to play some basketball in between hitting the books. Doctors are starting to find more and more information that suggests a connection between exercise and brain development. Judy Cameron, a scientist at Oregon Health and Science University, studies brain development. According to her research, it seems that exercise can make blood vessels (血管), including those in the brain, stronger and more fully developed. Dr. Cameron is sure that this allows people who exercise to think better. As she says, “While we already know that exercise is good for the heart, exercise can actually cause physical changes in the brain.”
The effects of exercise on brain development can even be seen in babies. Babies who do activities that require a lot of movement show greater brain development than babies who are less physically active. Even a little movement can show big results. Margaret Barnes, a scientist, also believes in the importance of exercise. She thinks that many learning disabilities that children have in primary school or high school can result from a lack of movement as babies. Babies need movement that encourages and excites their five senses. They need to set up a connection between motion and memory. In this way, as they get older, children will begin to connect physical activity with higher learning,” says Margaret.
Older people can develop their brains as well. Cornell University studied a group of seniors who have a short-term memory increase of up to 40 percent after exercising just three hours a week. The exercise does not have to be very difficult, but it does have to increase the heart rate. Also, just like the motion for babies, exercise for older people should not be too simple. Learning some new skills or actions, such as with yoga or tat- chi helps to open up memory paths in the brain that may not have been used for a long time. For most people, any type of physical activity that increases the heart rate is helpful. The main aim is to increase the brain’s flow of blood. And your brain can benefit from as little as two to three hours of exercise a week.
1.What is the main idea of this passage?
A. How exercise makes people strong.
B. How to get good scores in a test.
C. How exercise helps the brain develop.
D. How the brain can change one’s memory.
2.According to the passage, what is the connection between exercise and brain development?
A. Exercise helps soften our blood vessels.
B. Physical exercise helps us think better.
C. The brain needs special mental exercise.
D. The more exercise, the bigger the brain.
3.For ordinary people, the smallest amount of exercise required to gain any benefit is ______.
A. two hours per week B. 40 hours per week
C. three hours per day D. 40 hours per month
4.Why is yoga suggested for seniors?
A. It does good to the joints of old people.
B. It does not increase the heart rate.
C. It includes learning new actions.
D. It can be done in groups.
Many people are not aware the most healing herbs make up today’s modern medicine. The healing herbs from ancient days are still the healing herbs of modern times. Throughout all of these years herbs have remained unchanged; their quality remain as strong as ancient man and animals found it to be thousands of years ago. What has changed is the way man uses these healing herbs together with modern medicine of today.
Ancient man knew about the many benefits of healing herbs and passed on their knowledge form generation to generation. Today modern man continues to benefit from the wisdom ages ago. Actually, herbs can be any plant, flower, tree or shrub(灌木) that heals the body. According to early writings, man first noticed that when an animal was ill it would bite into specific plants, otherwise the animal will leave them alone.
Observing animal behaviors is still done today. Ten years ago, researchers at the Gombe Stream National Park in Tanzania, noticed chimpanzees(黑猩猩) that were ill were eating Aspirin leaves. Researchers found that Aspirin leaves contained a kind of antibiotic(抗生素). These chimpanzees no doubt knew this plant would help heal their disease.
Most plant life has a pleasant smell. The writings of ancient man note that people rubbed these sweet plants on their bodies to keep insects away.
Some herbs mask the smell of smelly meat. The Egyptians used a variety of herbs to preserve their dead.
In conclusion, ancient herbs had a variety of purposes, and for thousands of years were used for the preservation of our foods, and to heal our bodies. Herbs can continue to play an important part in our lives if we open our minds to their importance and usefulness. In my opinion, it is always better to treat naturally with herbs, than to treat illnesses with man-made medicines. There are few if any side effects to taking herbs.
1.The example of chimpanzees is used to suggest ________.
A. chimpanzees are clever animals
B. man began studying herbs long ago
C. Aspirin leave can cure many diseases
D. animals helped man discover healing herbs
2.According to the text, the Egyptians used herbs ________.
A. to keep off insects B. at the burial service
C. to feed their animals D. for the preservation of foods.
3.Which of the following about healing herbs isn’t introduced in the text?
A. How people knew about healing herbs.
B. The benefits of healing herbs.
C. Side effect of healing herbs.
D. How ancient people use healing herbs in life.
4.What is the author’s attitude towards healing herbs?
A. He thinks highly of them. B. He refuses to accept them.
C. He thinks they’re ineffective. D. He thinks they have side effects.
Finding out what kind and how much physical activity you need
How do I do it?
It’s your choice. Pick an activity that’s easy to fit into your life. Do at least 10 minutes of physical activity at a time. Choose aerobic activities that work for you. These make your heart beat faster and can make your heart, lungs, and blood vessels fitter. Also, do strengthening activities which make your muscles do more work than usual.
Why should I be physically active?
Physical activity can make you feel stronger and more alive. It is a fun way to be with your family or friends. It also helps you improve your health.
How many times a week should I be physically active?
It is up to you, but it is better to spread your activity throughout the week and to be active at least 3 days a week.
How do I build up more physical activity?
Do a little more each time. Once you feel comfortable, do it more often. Then you can trade activities at a moderate level for vigorous ones that take more effort. You can do moderate and vigorous activities in the same week.
How can I tell an activity at a moderate level from a vigorous one?
Vigorous activities take more effort than moderate ones. Here are just a few moderate and vigorous aerobic physical activities. Do these for 10 minutes or more at a time.
1.What is the main purpose of this text?
A. To give instruction in physics study.
B. To give advice on being physically active.
C. To urge people to abandon bad living habits.
D. To encourage students to be devoted to sports.
2.Which of the following is NOT mentioned as the advantage of being physically active?
A. Making you earn more.
B. Making your body healthier.
C. Making you feel more energetic.
D. Making your muscles work more effectively.
3.What would the author discuss in the paragraph that follows?
A. Kinds of moderate and vigorous activities.
B. Ways to get more information about physical activity.
C. The chart tells the activities that are important for you to do.
D. Aerobic activities and muscle strengthening activities.
听下面一段较长对话，回答以下小题。
1.Where did Nancy’s cancer begin?
A. In her heart. B. In her brain. C. On her skin.
2.According to the man, why was Nancy able to get better?
A. Because of the pills she was taking.
B. Because of her positive attitude.
C. Because of the food she was eating.
3.What will the new foundation focus on?
A. Helping families deal with cancer.
B. Giving money for cancer research.
C. Helping individuals with their medical bills.
4.How can people get more information about the foundation now?
A. By going online.
B. By emailing Dale and Nancy anytime.
C. By calling the speaker and his wife.
