Most people know precious gemstones (宝石) by their appearances. An emerald flashes deep green, a ruby seems to hold a red fire inside, and a diamond shines like a star. It’s more difficult to tell where the gem was mined, since a diamond from Australia or Arkansas may appear the same to one from the Democratic Republic of the Congo. However, recently, a team of scientists has found a way to identify a gemstone’s origin.
Beneath the surface of a gemstone, on the tiny level of atoms and molecules, lie clues to its origin. At this year’s meeting of the Geological Society of America in Minneapolis, Catherine McManus reported on a technique that uses lasers to clarify these clues and identify a stone’s homeland. McManus directs scientific research at Materialytics, in Killeen, Texas. The company is developing the technique. “With enough data, we could identify which country, which mining place, even the individual mine a gemstone comes from,” McManus told Science News.
Some gemstones, including many diamonds, come from war-torn countries. Sales of those “blood minerals” may encourage violent civil wars where innocent people are injured or killed. In an effort to reduce the trade in blood minerals, the U.S. government passed law in July 2010 that requires companies that sell gemstones to determine the origins of their stones.
To figure out where gemstones come from, McManus and her team focus a powerful laser on a small sample of the gemstone. The technique is called laser-induced breakdown spectroscopy. Just as heat can turn ice into water or water into steam, energy from the laser changes the state of matter of the stone. The laser changes a miniscule part of the gemstone into plasma, a gas state of matter in which tiny particles called electrons separate from atoms.
The plasma, which is superhot, produces a light pattern. (The science of analyzing this kind of light pattern is called spectroscopy.) Different elements produce different patterns, but McManus and her team say that gemstones from the same area produce similar patterns. Materialytics has already collected patterns from thousands of gemstones, including more than 200 from diamonds. They can compare the light pattern from an unknown gemstone to patterns they do know and look for a match. The light pattern acts like a signature, telling the researchers the origin of the gemstone.
In a small test, the laser technique correctly identified the origins of 95 out of every 100 diamonds. For gemstones like emeralds and rubies, the technique proved successful for 98 out of every 100 stones. The scientists need to collect and analyze more samples, including those from war-torn countries, before the tool is ready for commercial use.
Scientists like Barbara Dutrow, a mineralogist from Louisiana State University in Baton Rouge, find the technique exciting. “This is a basic new tool that could provide a better fingerprint of a material from a particular locality,” she told Science News. We learn from Paragraph 1 that __________________.
| A．an emerald and a ruby are names of diamonds. |
| B．it’s not difficult to tell where the gem was mined. |
| C．appearances help to identify the origin of gemstones. |
| D．diamonds from different places may appear the same. |
Why did the U.S. government pass law that requires companies selling gemstones to determine the origins of their stones?
| A．To look for more gemstones. |
| B．To encourage violent civil wars. |
| C．To reduce the trade in blood minerals. |
| D．To develop the economy. |
Which of the following facts most probably helps McManus and her team in identifying the origin of stones?
| A．Heat can turn ice into water or water into steam. |
| B．Gemstones from the same area produce similar light patterns. |
| C．Laser can changes a miniscule part of the gemstone into plasma. |
| D．Materialytics has already collected patterns from thousands of gemstones. |
From the last two paragraphs, what can be inferred about the laser technique?
| A．It is ready for commercial use. |
| B．People can use the new tool to find more gemstones. |
| C．It can significantly reduce the gemstones trade in blood minerals. |
| D．It will bring about a revolutionary change in identifying the origin of minerals. |
The author wrote this passage mainly to ________.
| A．tell us how to identify the origin of diamonds. |
| B．introduce a laser technique in identifying a stone’s origin |
| C．prove identifying the origin of gemstones are difficult |
| D．attract our attention to reducing trade in blood minerals |
Cleverness is a gift while kindness is a choice.Gifts are easy—they’re given after all.Choice can be hard.
I got the idea to start Amazon 16 years ago.I came across the fact that the Internet usage was growing at 2300 percent per year.I’d never seen or heard of anything that grew that fast，and the idea of building all online bookstore with millions of titles was very exciting to me. I had just turned 30 years old，and I’d been married for a year.I told my wife MacKenzie that I wanted to quit my job and go to do this crazy thing that probably wouldn’t work since most start-ups don’t and I wasn’t sure what to expect.MacKenzie told me I should go for it.As a young boy，I’d been a garage inventor.I’d always wanted to be all inventor，and she wanted me to follow my passion.
I was working at a financial firm in New York City with a bunch of very smart people and I had a brilliant boss that I much admired.I went to my boss and told him I wanted to start a company selling books on the Internet.He took me on a long walk in Central Park，listened carefully to me，and finally said，“That sounds like a really good idea，but it would be an even better idea for someone who didn’t already have a good job.”That 1ogic made some sense to me，and he convinced me to think about it for 48 hours before making a final decision.Seen in that light,it really was a difficult choice，but finally，I decided I had to give it a shot.I didn’t think I’d regret trying and failing.And I suspected I would always be haunted by a decision to not try at all.
After much consideration ，I took the less safe path to follow my passion ，and I’m proud of that choice.For all of us，in the end，we are our choice.What inspired the author with the idea of building an online bookstore?
| A．His dream of being an inventor. |
| B．The support of his wife. |
| C．The greatly increasing usage of the Internet. |
| D．Millions of exciting titles, |
Which of the following is closest in meaning to the underlined sentence?
| A．The idea of not trying would keep coming to his mind and disturb him. |
| B．He would be very excited if he tried it out. |
| C．Be would be always having a doubt if he didn’t try. |
| D．The decision to not try the online bookstore would terrify him. |
Which of the following would be the best title for the passage?
| A．Cleverness and Kindness | B．The Starting of Amazon |
| C．Following My Passion | D．We Are What We Choose |
We can know from the passage that_______.
| A．the boss thought the idea was suitable for the author |
| B．the author wanted someone else to try the idea |
| C．the author might not regret if he failed the idea |
| D．the author might go back to his boss if he failed |
Volunteering
Just like the animals we shelter, people are very special to us. The Animal Shelter of Sacramento County has 300 active volunteers and always wants to add more. If you have a few hours each week and a love for dogs and cats, we at the shelter welcome your coming.
Children 10 years of age or older are allowed to take part in some of our programs as youth volunteers when accompanied (陪伴) by an adult. The adult car be a parent, or guardian (监护人) 18 years of age or older
Youth Volunteer Opportunities
Youth volunteers may fill the position of dog nuzzler, cat snuggler, or kennel aide, if there are openings (空缺). Please call our volunteer information hotline at 1-800-290-5992 to hear a recording of the positions available.
Dog Nuzzlers
Dogs need human care and exercise to keep their health and level of comfort around people. Dog nuzzlers walk and clean the dogs staying at the shelter. Dog nuzzlers must be knowledgeable about dogs and able to deal with medium-sized to large-sized dogs. Youth volunteer dog nuzzlers must be able to work at least two hours between 9 A.M. and 5 P.M. on Sundays.
Cat Snugglers
Help our cats keep their lovely qualities by giving them lots of attention. Cat snugglers must be knowledgeable about cats and their needs. Youth volunteer cat snugglers must be able to work at least two hours between 9 A.M. and 5 P.M. on Saturdays.
Kennel Aides
Providing food and water for the animals at the shelter is a demanding job. Kennel aides assist the Animal Shelter staff in feeding the animals in our care. Kennel aides must be able to work at least two hours between 9 A.M. and 5 P.M. on either Saturdays or Sundays.
The main purpose of this text is to .
| A．look for youth volunteers |
| B．call on people to protect animals |
| C．introduce what the voluntary work is |
| D．teach people how to care for animals |
Any young person who wants to work shelter should .
| A．work all day long |
| B．be over 18 years old |
| C．call its information hotline first |
| D．have rich experience of raising animals |
What' s the duty of a kennel aide?
| A．To walk the animals. | B．To train the animals. |
| C．To feed the animals. | D．To treat the animals. |
Space is a dangerous place, not only because of meteors (流星) but also because of rays from the sun and other stars. The atmosphere again acts as our protective blanket on earth. Light gets through, and this is necessary for plants to make the food that we eat. Heat, too, makes our environment endurable. Various kinds of rays come through the air from outer space, but enormous quantities of radiation from the sun are screened off. As soon as men leave the atmosphere they are exposed to this radiation but their spacesuits or the walls of their spacecraft, if they are inside, do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space, The unit of radiation is called “rem” Scientists have reason to think that a man can put up with far more radiation than 0.1rem without being damaged; the figure of 60 rems has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damage. A person may feel perfectly well, but the cells of his or her sex organs may be damaged, and this will not be discovered until the birth of deformed children or even grandchildren. Missions of the Apollo flights have had to cross belts of high radiation and , during the outward and return journeys, the Apollo crew accumulated(积累) a large amount of rems. So far, no dangerous amounts of radiation have been reported, but the Apollo missions have been quite short. We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere, working in a space laboratory. Drugs might help to decrease the damage done by radiation, but no really effective ones have been found so far.In which way is the atmosphere necessary to man according to the first paragraph?
| A．It screens off the falling meteors. |
| B．It provides enough light for plants to grow. |
| C．It supplies the heat necessary for human survival. |
| D．It protects him against the harmful rays from space. |
We know from the passage that .
| A．exposure to even tiny amount of radiation is fatal( 致命的) |
| B．the effect of exposure to radiation is slow in coming |
| C．radiation is avoidable in space exploration |
| D．astronauts in spacesuits needn’t worry about radiation damage |
The underlined word “deformed” probably means .
| A．badly-shaped | B．weak |
| C．naturally-grown | D．ugly |
It can be inferred from the passage that .
| A．the Apollo mission was very successful |
| B．astronauts will have deformed children or grandchildren |
| C．protection from space radiation is no easy job |
| D．radiation is not a threat to well-protected space explorers |
Dear College Dean,
It is my understanding that this college has received a large donation to be used to enhance (improve) the quality of life for students: expand the bookstore or add computers to the computer lab. It is the tradition of this school to promote education and to be the pioneer of new technology. That is why I strongly argue in favor of the addition of more computers to the computer lab.
Although expanding the campus bookstore to include CDs, gifts, and a snack bar will give a nicer look to the college, we have to think about a greater goal and a more practical way to enhance the quality of life for students. What do we .want for our students and our college? Do we want our college to be known as a place with a great bookstore where you can find CDs and gifts, or as a place where the students can explore and research in their field using the best tools provided by technology? In addition, there are already several snack bars on campus, and there are music stores nearby, so students do not depend on the college bookstore for these things.
We live in a highly technological world and computers play an increasingly important role in how we live. As a learning institution, this college has the responsibility to offer its students the best technology to help them prepare for their future. Many students will be expected to be familiar with the latest software and other tools when they go on to work or to graduate school.
While they are in college, students find they are expected to use computers. Many professors expect students to use computers to do homework or to complete projects. Since students are competing for good grades, those who have limited access to computers are at a great disadvantage. Furthermore, being able to do projects using the computer enhances the process of learning.
If there are more computers, no more will students have to wait in line while scanning the room for an empty chair and computer.. No longer will they have to sit and wait while an outdated computer struggles to follow their commands. Having more new and faster computers available will enable students to finish their work more quickly.
The more computers are used in society, the more colleges will depend on them as a tool of teaching and learning. Making computers more available to students facilitates their learning process by making the process easier, more interesting, more engaging, and in the process enhancing their quality of life.From the passage we can infer that .
| A．present computers in the college cannot meet the demands of the students |
| B．computers in the college will be updated to meet the students’ demands soon |
| C．the college has the responsibility to help the students to prepare for their future |
| D．it is also necessary to expand the college bookstore by using part of the donation |
In paragraph 4，the author mainly wants to tell us that .
| A．computers are beneficial to students’ academic(学业) success |
| B．computers are helpful to students competition for success |
| C．students find it convenient to do assignments by using computers |
| D．students wish to use the money to buy more advanced computers |
Which of the following shows the organization of the passage?
CP: central point SP: sub-point(次要点) P: point C: conclusion
Louis Armstrong had two famous nicknames. Some people called him Bagamo. They said his mouth looked like a large bag. Musicians often called him Pops, as a sign of respect for his influence on the world of music.
Born in 1901 in New Orleans, he grew up poor, but lived among great musicians. Jazz was invented in the city a few years before his birth. Armstrong often said, “Jazz and I grew up together.”
Armstrong showed a great talent for music when he was taught to play the cornet (短号) at a boy’s home. In his late teens, Armstrong began to live the life of a musician. He played in parades, clubs, and on the steamboats that traveled on the Mississippi River. At that time, New Orleans was famous for the new music of jazz and was home to many great musicians. Armstrong learned from the older musicians and soon became respected as their equal. In 1922 he went to Chicago. There, the tale of Louis Armstrong begins. From then until the end of his life, Armstrong was celebrated and loved wherever he went. Armstrong had no equal when it came to playing the American popular song.
His cornet playing had a deep humanity and warmth that caused many listeners to say,“Listening to Pops just makes you feel good all over.” He was the father of the jazz style and also one of the best-known and most admired people in the world. His death, on July 6, 1971, was headline news around the world.Armstrong was called Pops because he .
| A．looked like a musician |
| B．was a musician of much influence |
| C．showed an interest in music |
| D．traveled to play modern music |
The third paragraph is developed .
| A．by space | B．by examples |
| C．by time | D．by comparison |
Which statement about Armstrong is true?
| A．His tale begins in New Orleans. |
| B．He was born before jazz was invented. |
| C．His music was popular with his listeners. |
| D．He learned popular music at a boy’s home. |
Which would be the best title for the text?
| A．The Invention of the Jazz Music |
| B．The Father of the Jazz Style |
| C．The Making of a Musician |
| D．The Spread of Popular Music |