Have you ever wondered why the roots of the plants always know which way to grow—into the soil but not above it? Some British scientists have recently solved this mystery.
It turns out that roots have special hairs that tie them into the soil and help them grow their way past obstacles, a team at the John Inners Center in Norwich reports in the February 29 issue of Journal Science.
“The key is in the fuzzy(有绒毛的)coat of hairs on the roots of plants,” says professor Liam Dolan. “We have found a growth control system that enables these hairs to find their way and to become longer when their path is clear.”
Root hairs explore the soil in much the same way a person would feel their way in the dark. If they come across an obstacle, they make their way around until they can continue growing in an opening. In the meantime, the plant is held in place as the hairs grip(紧紧抓住)the soil.
The hairs are guided by a clever chemical trick. A protein(蛋白质) at the tip of the root hairs called RHD2 helps them to take calcium(钙) from the soil. Calcium makes the hairs grow, and produce more RHD2, and take more calcium.
But when an obstacle blocks the hair’s path, or the hair reaches the surface of the soil, the cycle is broken and growth starts in another direction.
This system gives plants the flexibility to explore a complex environment and to live in even the most unpromising soils, says Dolan.
In poor soils such as in parts of Australia and Africa, native plants have adapted by producing enormous numbers of root hairs. A better understanding of this adaptation will allow scientists to develop hairy rooted crops that can grow in unfriendly environments.
According to Dolan, “Research in the John Inners Center is taking a breeding approach to increase hair length in wheat but it will be some time before new cultivars(栽培变种) are developed.”The passage is mainly about _______.
| A．why the roots of plants grow into the soil but not above it |
| B．how the roots of plants grow into the soil but not above it |
| C．the process of plants growth |
| D．a growth control system of plants |
How does the circle work?
| A．RHD2 takes calcium from the soil, which makes hairs grow, and produce RHD2 and take more calcium |
| B．Roots take RHD2 and calcium from the soil and produce RHD2 |
| C．Roots make hairs grow, and produce RHD2, and take more calcium |
| D．RHD2 takes protein, which makes hairs grow, and produce RHD2, and take more calcium |
We can infer from the last paragraph that ________.
| A．hairy rooted crops can grow better in unfriendly environments |
| B．a new cultivar of wheat with long hair has been developed by scientists |
| C．a new cultivar of wheat with long hair is still on test |
| D．the roots of plants always know which way to grow |
Terrafugia Company has said that its flying car, named Transition, has successfully finished a 37- second test flight
On March 5, 2009, at Plattsburgh International Airport in New York. It was piloted by Phil Meteer, the company's chief pilot.
Transition is a two-seat airplane that can take off and land at airports as well as drive on roads.
The company said that the flying car can travel at speeds up to 115 mph for 450 miles in the air, drive at highway speeds on the ground, and fold up(折叠) to fit in a garage (车库) 81 inches wide, and 80 inches high.
This could be used in hospitals to transport patients so as to avoid road traffic. It may start running on wheels, and when it gets to traffic lights it can fly overhead the lights and keeps its way forward. So it’s good news to avoid traffic problem and the traffic accidents.
But some people say this is a going airplane rather than a flying car, at least on the appearance. Anyway, we are happy for scientific-technical progress, what a fantastical world in the near future! This kind of new machine is made by ______.
| A．Phil Meteer |
| B．Terrafugia Company |
| C．Plattsburgh International Airport |
| D．both A and B |
___ people can sit in Transition.
| A．3 | B．5 | C．4 | D．2 |
Transition can travel ____ miles every hour in the air .
| A．115 | B．120 | C．450 | D．480 |
Which of the following sentences about Transition is not true? __________.
| A．It can be folded up. |
| B．It can both run on the ground and fly in the sky. |
| C．It is used in hospital now. |
| D．It looks like a plane . |
One night, a little before nine o’clock, Dr Johnson was answering a telephone call. He was asked to go and give an operation to a very sick boy at once. The boy was in a small hospital in Glens Falls, sixty miles away from Dr Johnson’s city – Albany. The boy had hurt himself in a traffic accident. His wife was in danger, but his family was so poor that they could not pay the doctor anything. After he heard all this, Dr Johnson was driving carefully. He thought that he could get to the hospital before 12 o’clock. A few minutes later, the doctor’s car had to stop for a red light at a crossing. Suddenly a man in an old black coat opened the door of the car and got in.
“Drive on”, he said. “I’ve got a gun (枪).”
“I’m a doctor,” said Johnson, “I’m on my way to a hospital to operate on a very sick…”
“Don’t talk,” said the man in the old black coat, “Just drive.”
A mile out of the town he ordered the doctor to stop the car and get out. Then the man drove on down the road. The doctor stood for a moment in the snow. After half an hour, Dr Johnson found a telephone and called a taxi. At the railway station he learned that the next train to Glens Falls would not leave until 12 o’clock.
It was after two o’clock in the morning when the doctor arrived at the hospital in Glens Falls. Miss Clarke, a nurse, was waiting for him.
“I did my best,” said Dr Johnson. Miss Clarke said, “The boy died an hour ago.”
They walked into the waiting room. There sat the man in the old black coat, with his head in his hands.
“Mr. Shute,” said Miss Clarke to the man, “this is Dr Johnson. He had come all the way from Albany to try to save your boy.” From the story we know it took Dr Johnson _________ to get to the hospital.
| A．12 hours | B．7 hours | C．only 1 hour | D．about 5 hours |
Dr Johnson was late because __________.
| A．there was something wrong with his car |
| B．a strange man made it hard to drive |
| C．a strange man drove his car away |
| D．the train to Glens Falls was late |
The man in a black coat __________.
| A．hit the boy and ran away |
| B．took the boy to the hospital |
| C．was the boy’s father |
| D．was the real doctor |
The man in black would feel __________ in the end.
| A．happy and pleased | B．regretful(悔恨) and sad |
| C．worried and angry | D．tired and hungry |
Happiness is for everyone. You don’t need to care about those people who have beautiful houses with large gardens and swimming pools or those who have nice cars and a lot of money and so on. Why? Because those who have big houses may often feel lonely and those who have cars may want to walk on the country roads at their free time.
In fact, happiness is always around you if you put your heart into it. When you are in trouble at school, your friends will help you; when you study hard at your lessons, your parents are always taking good care of your life and your health; when you get success, your friends will say congratulations to you; when you do something wrong, people around you will help you to correct it. And when you do something good
to others, you will feel happy, too. All these are your happiness. If you notice them, you can see that happiness is always around you.
Happiness is not the same as money. It is a feeling of your heart. When you are poor, you can also say you are very happy, because you have something else that can’t be bought with money. When you meet with difficulties, you can say loudly you are very happy, because you have more chances to challenge yourself. So you cannot always say you are poor and you have bad luck. As the saying goes, life is like a revolving(旋转 ) door. When it closes, it also opens. If you take every chance you get, you can be a happy and lucky person. When you do something wrong, _______________.
| A．you may correct it |
| B．you will have no chance to challenge yourself |
| C．anybody will laugh at you |
| D．you will be happy |
Which is TRUE according to the passage?
| A．When you get success, your friends will be very proud of you. |
| B．You can get help from others when you make mistakes. |
| C．You can still be a happy person even if you have little money. |
| D．All the above. |
Why do we say “Happiness is not the same as money”? Because _______________.
| A．money always brings happiness |
| B．money doesn’t always bring happiness |
| C．everything can be bought with money |
| D．only rich people have happiness |
Which is the title of the passage?
| A．Do Something Good to Others |
| B．Happy and Lucky |
| C．Happiness |
| D．Life and Success |
From a plane we can see the fields, cities, mountains or seas below. If we go into space, we see more and more of the earth. People and man-made satellites have been sent out into space to look at the earth carefully and people have learnt more about the earth in the last few years.
The sea looks very beautiful when the sun is shining on it. But it can be very terrible when there is a strong wind.
The sea is very big. It nearly covers three quarters of the earth. The sea is also very deep in some places. There is one place and at that place the sea is about 11 kilometers deep. The highest mountain in the world is about 9 kilometers high. If that mountain was put into the sea at that place, there would be still 2 kilometers of water above it!
In most parts of the sea, there are many kinds of fishes and plants. Some live near the top of the sea. Others live deep down. There are also a lot of small living things, and lots of fishes live by eating them.
The sea can be very cold. When people go down, the sea becomes colder and colder. Only some men can go down into the deep sea. But, in 1970, five women scientists (科学家) lived in the deep sea for fourteen days.This passage is_________.
| A．a short story | B．for science reading |
| C．a piece of news | D．a report |
The sea covers about _______of the earth.
A One third B. One fourth
C. Two quarters D. Three fourths Which of the following is NOT true?
| A．The sea is usually beautiful when the sun is shining. |
| B．The sea is always very terrible when the wind blows hard. |
| C．The highest mountain is in the deepest place of the sea. |
| D．The deeper the people go into the sea, the colder they will feel. |
The last sentence “But, in 1970, five women scientists lived in the deep sea for fourteen days.” means that________.
| A．women wanted to live in the deep sea for a long time |
| B．women could go deeper into the sea than men |
| C．women liked living in the deep sea better than men |
| D．women could do the same work as men |
What happens to a teenage kid when the world he thought he knew suddenly changes? Find out in Little Brother by American author Cory Doctorow. It is a fascinating book for a new generation of sci-fi readers.
Marcus Yallow, 17, from San Francisco is much more comfortable in front of a computer than obeying the rules of society. Smart, fast and wise to the ways of the networked world, he has no trouble outwitting (骗过) his high school's monitoring system. This way he and his friends get to head off to play a popular online game in real life.
While they are playing, a bomb explodes on the Bay Bridge. Marcus stops a military (军队的) vehicle to get help for his injured friend, but this simple act throws him into a Department of Homeland Security (DHS) secret prison. There he is treated as a possible terrorist(恐怖分子). He is eventually let go after four days, but his injured friend disappears.
When he returns, Marcus discovers that there are many "security measures" in place and that now all citizens are treated like potential terrorists. While some consider this government action necessary for public safety, Marcus sees this as a complete destruction of the rights he is supposed to have as a citizen.
He knows that no one will believe his story, which leaves him with only one thing to do: to take down the DHS himself. He helps organize a large network called Xnet to spread the truth, anonymously (匿名地).
The book presents a young man who is irresponsible, but learns about himself, and grows, in the course of the story. As part of this learning and growing he becomes aware of very serious issues about his society. What kind of article does this passage belong to?
| A．A fascinating story. | B．A book review. |
| C．News report | D．A TV programme |
Marcus Yallow was sent to prison because ________.
| A．he killed his friend |
| B．he bombed a military vehicle |
| C．he did something that a possible terrorist could do |
| D．his injured friend disappeared |
From the second paragraph we can infer that _________.
| A．Marcus Yallow is much more comfortable obeying the rules of society |
| B．Marcus Yallow is smart, fast and wise in real life |
| C．Marcus Yallow always plays online games in real life |
| D．Marcus Yallow is expert at the network world |
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