Scientists are trying to make the deserts into good land again．They want to bring water to the deserts，so people can live and grow food．They are learning a lot about the deserts．But more and more of the earth is becoming desert all the time．Scientists may not be able to change the desert in time．
Why is more and more land becoming desert？Scientists think that people make deserts．People are doing bad things to the earth．
Some places on the earth don’t get much rain． But they still don’t become deserts． This is because some green plants are growing there． Small green plants and grass are very important to dry places． Plants don’t let the sun make the earth even drier． Plants do not let the wind blow the dirt away． When a bit of rain falls， the plants hold the water． Without plants， the land can become desert more easily． Deserts ＿＿＿＿＿＿＿＿ ．
| A．never have any plants or animals in them |
| B．can all be turned into good land before long |
| C．are becoming smaller and smaller |
| D．get very little rain |
Small green plants are very important to dry places because ＿＿＿＿＿＿＿＿ ．
| A．they don’t let the sun make the earth even drier |
| B．they don’t let the wind blow the soil away |
| C．they hold water |
| D．All of the above． |
Land is becoming desert little by little because ＿＿＿＿＿＿．
| A．plants can’t grow there |
| B．there is not enough rain |
| C．people haven’t done what scientists wish them to do |
| D．scientists know little about the deserts |
Why is more and more land becoming desert according to this passage？
| A．Earthquakes make deserts. | B．Wind makes deserts. |
| C． Lack of water makes deserts. | D．People make deserts． |
Can people change their skin colour without suffering like pop king Michael Jackson? Perhaps yes. Scientists have found the gene that determines skin colour.
The gene comes in two versions, one of which is found in 99 per cent of Europeans. The other is found in 93 to 100 per cent of Africans, researchers at Pennsylvania State University report in the latest issue of Science.
Scientists have changed the colour of a dark-striped zebrafish to uniform gold by inserting a version of the pigment(色素) gene into a young fish. As with humans, zebrafish skin colour is determined by pigment cells, which contain melanosomes(黑色素). The number, size and darkness of melanosomes per pigment cell determines skin colour.
It appears that, like the golden zebrafish, light-skinned Europeans also have a mutation(变异) in the gene for melanosome production. This results in less pigmented skin.
However, Keith Cheng, leader of the research team, points out that the mutation is different in human and zebrafish genes.
Humans acquired dark skin in Africa about 1.5 million years ago to protect bodies from ultra-violet rays(紫外线) of the sun, which can cause skin cancer.
But when modern humans leave Africa to live in northern latitudes, they need more sunlight on their skin to produce vitamin D. So the related gene changes, according to Cheng.
Asians have the same version of the gene as Africans, so they probably acquired their light skin through the action of some other gene that affects skin colour, said Cheng.
The new discovery could lead to medical treatments for skin cancer. It also could lead to research into ways to change skin colour without damaging it like chemical treatment did on Michael Jackson.What is the main idea of the passage?
| A．People can’t change their skin colour without any pain. |
| B．The new discovery helped find ways to change skin colour safely. |
| C．Pop king Michael Jackson often changed his skin colour as he liked. |
| D．Scientists have found out that people’s skin colour is determined by the gene. |
It can be inferred from the passage that ________.
| A．nowadays changing the skin colour with the chemical treatment has bad effect |
| B．Europeans and Africans have the same genes |
| C．the new discovery could help to find medical treatments for skin cancer |
| D．there are two kinds of skin genes |
Scientists have done an experiment on a dark-striped zebra fish in order to ________.
| A．find the different genes of humans |
| B．prove the humans’ skin colour is determined by the pigment gene |
| C．find out the reason why the Africans’ skin colour is dark |
| D．find out the ways of changing people’s skin colour |
Which of the following statements is TRUE?
| A．Michael Jackson died of skin damage caused by chemical treatment. |
| B．American blacks produce more vitamin D with their skin than others. |
| C．The gene determining skin colour exists widely in whites, blacks and Asians. |
| D．The melanosomes in the skin of blacks usually cause skin cancer more often. |
She may have lacked a home, but now this teen has top honors.
A 17-year-old student who spent much of high school living around homeless shelters — and sometimes sleeping in her car — today graduated and spoke on behalf of her class at Charles Drew High School in Clayton County, Ga., just outside of Atlanta.
Chelsea Fearce held a 4.466 GPA and scored 1900 on her SATs despite having to use her cellphone to study after the shelter lights were turned off at night.
“I know I have been made stronger. I was homeless. My family slept on cushions on the floor and we were lucky if we got more than one full meal a day. Getting a shower, food and clean clothes was an everyday struggle,” Fearce said in a speech she gave at her graduation ceremony. Fearce overcame her day-to-day struggles by focusing on a better day. “I just told myself to keep working, because the future will not be like this anymore,” she told WSBTV.
Fearce, one of five children, grow up in a family that sometimes had an apartment to live in, but at other times had to live in homeless shelters or even out of their car, if they had one. “You’re worried about your home life and then worried at school. Worry about being a little hungry sometimes and go hungry sometimes. You just have to deal with it. You eat what you can, when you can.”
To our surprise, Fearce overcame the difficulties and even tested high enough to be admitted into college half way through her high school career. She starts college next year at Spelman College as a junior where she is planning to study biology, pre-med (医学预科). “Don’t give up. Do what you have to do right now so that you can have the future that you want,” Fearce said.How did Fearce go on with her study without access to lights?
| A．By the car light. |
| B．By her cellphone. |
| C．By lights out of shelters. |
| D．By moonlight. |
When Fearce starts college at Spelman College, she will _____..
| A．have graduated earlier from high school than normal |
| B．be a 17-year-old student from a poor family |
| C．have a home without sleeping in her car or shelters |
| D．have raised enough money to go to college |
What lesson can we learn from Fearce’s experience?
| A．Knowledge can change your fate. |
| B．Don’t give up, and tomorrow will be better. |
| C．Whatever is worth doing is worth doing well. |
| D．He that will not work shall not eat. |
In the mid-1950s, I was a somewhat bored early-adolescent male student who believed that doing any more than necessary was wasted effort. One day, this approach threw me into embarrassment
In Mrs. Totten’s eighth-grade math class at Central Avenue School in Anderson, Indiana, we were learning to add and subtract decimals (小数).
Our teacher typically assigned daily homework, which would be recited in class the following day. On most days, our grades were based on our oral answer to homework questions.
Mrs. Totten usually walked up and down the rows of desks requesting answers from student after student in the order the questions had appeared on our homework sheets. She would start either at the front or the back of the classroom and work toward the other end.
Since I was seated near the middle of about 35 students, it was easy to figure out which questions I might have to answer. This particular time, I had completed my usual two or three problems according to my calculations.
What I failed to expect was that several students were absent, which threw off my estimate. As Mrs. Totten made her way from the beginning of the class，I desperately tried to determine which math problem I would get. I tried to work it out before she got to me, but I had brain freeze and couldn’t function.
When Mrs. Totten reached my desk，she asked what answer I’d got for problem No. 14. “I…I didn’t get anything,” I answered，and my face felt warm.
“Correct,” she said.
It turned out that the correct answer was zero.
What did I learn that day? First, always do all your homework. Second, in real life it isn’t always what you say but how you say it that matters. Third，I would never make it as a mathematician.
If I could choose one school day that taught me the most, it would be that one.What does the underlined part in Paragraph 1 indicate?
| A．It is wise to value one’s time. |
| B．It is important to make an effort |
| C．It is right to stick to one’s belief. |
| D．It is enough to do the necessary. |
Usually, Mrs. Totten asked her students to _______.
| A．recite their homework together |
| B．grade their homework themselves |
| C．answer their homework questions orally |
| D．check the answers to their homework questions |
The author could work out which questions to answer since the teacher always _______.
| A．asked questions in a regular way |
| B．walked up and down when asking questions |
| C．chose two or three questions for the students |
| D．requested her students to finish their usual questions |
The author failed to get the questions he had expected because _______.
| A．the class didn’t begin as usual |
| B．several students didn’t come to school |
| C．he didn’t try hard to make his estimate |
| D．Mrs. Totten didn’t start from the back of the class |
Which of the following can be the best title for the passage?
| A．An Unforgettable Teacher | B．A Future Mathematician |
| C．An Effective Approach | D．A Valuable Lesson |
People aren’t walking any more---if they can figure out a way to avoid it.
I felt superior about this matter until the other day I took my car to mail a small parcel. The journey is a matter of 281 steps. But I used the car. And I wasn’t in any hurry, either, I had merely become one more victim of a national sickness: motorosis.
It is an illness to which I had thought myself immune(免疫的), for I was bred in the tradition of going to places on my own two legs. At that time, we regarded 25 miles as good day’s walk and the ability to cover such a distance in ten hours as sign of strength and skill. It did not occur to us that walking was a hardship. And the effect was lasting. When I was 45 years old I raced –and beat—a teenage football player the 168 steps up the Stature of Liberty.
Such enterprises today are regarded by many middle-aged persons as bad for the heart. But a well-known British physician, Sir Adolphe Abrhams, pointed out recently that hearts and bodies need proper exercises. A person who avoids exercise is more likely to have illnesses than one who exercises regularly. And walking is an ideal form of exercise--- the most familiar and natural of all.
It was Henry Thoreau who showed mankind the richness of going on foot. The man walking can learn the trees, flower, insects, birds and animals, the significance of seasons, the very feel of himself as a living creature in a living world, He cannot learn in a car.
The car is a convenient means of transport, but we have made it our way of life. Many people don’t dare to approach Nature any more; to them the world they were born to enjoy is all threat. To them security is a steel river thundering on a concrete road. And much of their thinking takes place while waiting for the traffic light to turn green.
I say that the green of forests is the mind’s best light. And none but the man on foot can evaluate what is basic and everlasting.What is the national sickness?
| A．Walking too much | B．Traveling too much |
| C．Driving cars too much | D．Climbing stairs too much. |
What was life like when the author was young?
| A．People usually went around on foot. |
| B．people often walked 25 miles a day |
| C．People used to climb the Statue of Liberty. |
| D．people considered a ten-hour walk as a hardship. |
The author mentions Henry Thoreau to prove that
| A．middle-aged people like getting back to nature |
| B．walking in nature helps enrich one’s mind |
| C．people need regular exercise to keep fit |
| D．going on foot prevents heart disease |
What is compared to “a steel river” in Paragraph6?
| A．A queue of cars | B．A ray of traffic light |
| C．A flash of lightning | D．A stream of people |
What is the author’s intention of writing this passage?
| A．To tell people to reflect more on life. |
| B．To recommend people to give up driving |
| C．To advise people to do outdoor activities |
| D．To encourage people to return to walking |
Scientists today are making greater effort to study ocean currents (洋流) . Most do it using satellites and other high-tech equipment. However, ocean expert Curtis Ebbesmeyer does it in a special way --- by studying movements of random floating garbage. A scientist with many years’ experience, he started this type of research in the early 1990s when he heard about hundreds of athletic shoes washing up on the shores of the northwest coast of the United States. There were so many shoes that people were setting up swap meets to try and match left and right shoes to sell or wear.
Ebbesmeyer found out in his researches that the shoes — about 60,000 in total — fell into the ocean in a shipping accident. He phoned the shoe company and asked if they wanted the shoes back. As expected, the company told him that they didn't. Ebbesmeyer realized this could be a great experiment. If he learned when and where the shoes went into the water and tracked where they landed, he could learn a lot about the patterns of ocean currents.
The Pacific Northwest is one of the world's best areas for beachcombing(海滩搜寻) because winds and currents join here, and as a result, there is a group of serious beachcombers in the area. Ebbesmeyer got to know a lot of them and asked for their help in collecting information about where the shoes landed. In a year he collected reliable information on 1, 600 shoes. With this data, he and a colleague were able to test and improve a computer program designed to model ocean currents, and publish the findings of their study.
As the result of his work, Ebbesmeyer has become known as the scientist to call with questions about any unusual objects found floating in the ocean. He has even started an association of beachcombers and ocean experts, with 500 subscribers from West Africa to New Zealand. They have recorded all lost objects ranging from potatoes to golf gloves.The underlined phrase swap meets in Paragraph 1 is closest in meaning to ___________.
| A．fitting rooms | B．trading fairs |
| C．business talks | D．group meetings |
Ebbesmeyer phoned the shoe company to find out ___________.
| A．what caused the shipping accident |
| B．when and where the shoes went missing |
| C．whether it was all right to use their shoes |
| D．how much they lost in the shipping accident |
How did Ebbesmeyer prove his assumption?
| A．By collecting information from beachcombers. |
| B．By studying the shoes found by beachcomber. |
| C．By searching the web for ocean currents models. |
| D．By researching ocean currents data in the library. |
Ebbesmeyer is most famous for _________________.
| A．traveling widely the coastal cities of the world |
| B．making records for any lost objects on the sea |
| C．running a global currents research association |
| D．phoning about any doubtful objects on the sea |
What is the purpose of the author in writing this passage?
| A．To call people's attention to ocean pollution. |
| B．To warn people of shipping safety in the ocean. |
| C．To explain a unique way of studying ocean currents. |
| D．To give tips on how to search for lost objects on the beach. |