Lead（铅） deposits, which accumulated（增加） in soil and snow during the 1960's and 70's, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated（托管） unleaded gas use in the United States, the lead accumulation world-wide has decreased greatly.
A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining（减少）.
In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasoline and thus enabled scientists to differentiate (分区) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States.
In a study published in the journal Ambio, scientists found that lead levels in soil in the North-eastern United States had decreased markedly since the introduction of unleaded gasoline. Many scientists had believed that the lead would stay in soil and snow for a longer period.
The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed (再分配)the lead faster than the scientists had expected. Scientists say both studies show that certain parts of the ecosystem (生态系统 ) respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.
1. The study published in the journal Nature indicates that ________.
A. the Clean Air Act has not produced the desired results
B. lead deposits in arctic snow are on the increase
C. lead will stay in soil and snow longer than expected
D. the US is the major source of lead pollution in arctic snow
2. Lead accumulation worldwide decreased significantly after the use of unleaded gas in the US ________.
A. was discouraged B. was carried out by law
C. was forbidden by law D. was introduced
3. How did scientists discover the source of lead pollution in Greenland?
A. By analyzing the data published in journals like Nature and Ambio.
B. By observing the lead accumulations in different parts of the arctic area.
C. By studying the chemical elements of soil and snow in Northeastern America.
D. By comparing the chemical compositions of leaded gasoline used in various countries.
4. The authors of the Ambio study have found that ________.
A forests get rid of lead pollution faster than expected
B. lead accumulations in forests are more difficult to deal with
C. lead deposits are widely distributed in the forests of the US
D. the upper layers of soil in forests are easily polluted by lead emissions
5. It can be inferred from the last paragraph that scientists ________.
A. are puzzled by the mystery of forest pollution
B. feel ease by the use of unleaded gasoline
C. still consider lead pollution a problem
D. lack enough means to combat lead pollution
March 21 has been declared World Sleep Day, a time to recognize and celebrate the value of sleep. Many sleep experts hope it will be a wake-up call.
According to a poll (民意调查）by the National Sleep Foundation, nearly 4 in 5 Americans don’t get as much sleep as they should during the workweek. On average, adults are thought to need at least eight hours of sleep a night, although some can manage with less and some won’t do well without more. But the survey found that, on workdays, only 21% of Americans actually get a full eight hours of sleep, and another 21% get less than six.
To many of us, the thought of spending more time sleeping is, well, a big yawn. On the other hand, the thought of being smarter, thinner, healthier and more cheerful has a certain appeal. And those are just a few of the advantages that can be ours if we consistently get enough sleep, researchers say. Also on the plus side: We’re likely to have better skin, better memories, better judgment, and, oh, yes, longer lives.
“When you lose even one hour of sleep for any reason, it influences your performance the next day,” says Dr. Alon Avidan, director of the UCLA Sleep Disorders Center.
A study published last year found the same to be true even of children. When kids aged 8 to 12 slept for just one hour less for four nights, they didn’t function as well during the day.
But sleeping has an image problem. “We see napping or sleeping as lazy,” says Jennifer Vriend, a clinical psychologist in Ottawa, Canada, and the leading author of the study with children. “We put so much emphasis on diet, nutrition and exercise. Sleep is in the back seat.” In fact, she adds, no matter how much we work out, no matter how well we eat, we can’t be in top physical shape unless we also get plenty of sleep.
The underlined part in Paragraph 1 means _____.
| A．To wake up the sleepers |
| B．To draw people’s attention |
| C．To serve as a morning call |
| D．To declare the special day |
From Paragraph 3 we can infer that _______
| A．Being healthier is one of the advantages for us |
| B．Sleeping has nothing to do with one’s expectations |
| C．Spending more time on sleeping is a waste of time |
| D．Enough sleep is the guarantee of the appealing things |
What Jennifer Vriend said in the last paragraph implies that _______.
| A．Sleeping is an image problem |
| B．People care little about sleeping |
| C．Lazy people tend to sleep long |
| D．Sleeping is only part of our life |
What is the purpose of the passage?
| A．To talk about people’s sleeping problems. |
| B．To provide an investigation result of sleeping. |
| C．To arouse the awareness of enough sleeping. |
| D．To stress the function of sleeping at night. |
One day I was driving home with a woman. She rolled down the window, fifty feet away from the driveway and spit her gum （口香糖）out of the window. “Couldn’t you just wait five seconds and put your gum where it belongs?” I asked, annoyed.
She was not the only one who was gum-lazy. Consider the following. Every time I brush chewed gum under my desk, I shake with fright. At Folsom Middle School, whenever I had to walk by the gum wall next to the girls’ locker room, I felt totally disgusted. When I was young, I walked outside during my dance show in my ballet shoes, always stepping right on a big and juicy piece of bubble gum. I was extremely upset.
The worst part of all these incidents is that a trash can is located near. But some people are too lazy to walk towards it.
If you can’t be a responsible gum chewer, don’t chew at all. That’s all I’m going to say.
Take Singapore as a good example. The chewing gum ban in Singapore was placed. It bans the import and sale of chewing gum in Singapore, whether for the purpose of trade or personal chewing. However, the ban has been partly lifted with some types of gum, such as medical gum, allowable. This comes with the warning that it is sold only by a druggist, who has to take down the names of buyers. Obviously, the Singapore government gets angry at gum stuck in keyholes of mailboxes and on elevator buttons.
Not only is it annoying, but chewing gum can actually do harm to the health. Most gum contains aspartame （阿斯巴甜）, a chemical sweetener（增甜剂）that the US government is now deciding whether or not it is a deadly chemical. If it is, it may cause cancer. Other studies suggest that aspartame may cause neurological（神经系统的）disorders. Therefore, aspartame is not allowed to use in the US.
So just say no to chewing gum.What did the author think of the woman’s behavior?
| A．It was strange. | B．It was unacceptable. |
| C．It was dangerous. | D．It was violent. |
According to Paragraph 2, the author _________.
| A．stepped on a piece of gum while dancing |
| B．cleaned gum under her desk sometimes |
| C．was troubled by chewed gum |
| D．often found chewed gum in her locker |
What do we know about aspartame?
| A．It is proved to be a harmless chemical. |
| B．It is the cause of many kinds of cancer.. |
| C．It is being refused by the US government. |
| D．It is the main ingredient of chewing gum. |
What is the main purpose of the text?
| A．To advise people against chewing gum. |
| B．To criticize people who are lazy. |
| C．To persuade people to buy medical gum. |
| D．To make comments on the ban in Singapore. |
2016 International Summer School
The 2016 University of Cambridge International Summer Schools will run in Cambridge from 6 July to 22 August 2016. Our programs give you the opportunity to meet award-winning lecturers, stay and dine in one of the historic Cambridge Colleges and enjoy a range of weekend excursions（游览）and social activities. To sign up for a program simply apply online, or download an application form from our website. Places on courses and in-college accommodation are limited, so we encourage applicants to apply early to avoid disappointment.
This year we will be offering specialist programs in: Ancient Empires, Literature, History, Medieval Studies and new for 2016, Creative Writing and Hanseatic League. If you are looking to study a number of different subject areas, the Interdisciplinary Summer School is ideal. It is divided into three terms, Interdisciplinary Summer School Term I, Interdisciplinary Summer School Term II and Interdisciplinary Summer School Term III, covering a wide range of subjects including politics, philosophy, economics, literature, history and international relations. You can opt to do one or two terms. But most students choose all the three terms.
The Cambridge English for Academic Purposes program combines a two-week intensive（强化）language course with a two-week academic program. This allows students to put into practice the language skills they have learned during the first two weeks of the program. Applicants will also have the opportunity to sign up for weekend excursions and take part in various events.
If you want to join us in 2016, please click here to download a copy of brochure（手册）. If you want to find out more information about 2016 International Summer School, you can visit www.ice.cam.ac.uk/intsummer. (CLICK HERE)
What our students say
“The entire experience was even better than I expected. I absolutely loved it.” Sally, USA
“I believe that the Science International Summer School was a fulfilling experience. I think that everyone should attend this Summer School at least once in a lifetime.” Dominika, PolandWhat should people do if they want to sign up for a program in this ad?
| A．They should go to Cambridge by plane. |
| B．They should phone Cambridge. |
| C．They should call for an application form. |
| D．They should apply for the program online. |
Why are the applicants encouraged to apply early?
| A．The earlier they apply, the less they will pay. |
| B．If they apply late, they have to live out of Cambridge College. |
| C．There are not enough places for the courses or in-college accommodation. |
| D．The reason is not mentioned in the passage. |
What’s the meaning of the underlined word in Paragraph 3?
| A．To avoid doing a duty |
| B．To choose to do |
| C．To decide not to be part of a group |
| D．To decide on |
If man’s best friend is a dog, then who is a dog’s best friend? That would be Rover, Glow, Ivan or Raina. They recently donated (捐赠) blood to other dogs. And they did it without having to travel far from home: they visited an animal bloodmobile.
Like the Red Cross vehicles for humans, the University of Pennsylvania’s traveling vet lab goes to where the donors are to make it easier to give. The bloodmobile makes weekly rounds through Philadelphia and New Jersey.
Like humans, not every dog is qualified(合格的) to donate blood. The dogs are examined for health first. Dogs must have the correct blood type, weigh at least 55 pounds and be under 8 year old. About 150 dogs take part in the program. Each donates three or four pints(品脱) a year, which can help animals suffering from illness like cancer or an accident like being hit by a car.
Sandy Lucas brought her 7-year-old dog, Raina, to the bloodmobile last week. She said she wouldn’t have taken the dog to Penn Vet’s animal hospital in downtown Philadelphia, which is twice as far from her home. “I was very, very excited that she had the right blood that was needed to help another dog out,” said Lucas. “We’ll surely do it again.”
Just like people, the donors get a snack and a heart-shaped sticker immediately after giving. What’s more, they receive dog food to take home.
If dogs are doing what they can to save other dogs, why can’t we do it to save other people? Next time you hesitate(犹豫) over whether to donate blood or not, think of the dogs.The writer mentions Rover, Glow, Ivan and Raina in Para. 1 mainly because _________.
| A．they are man’s best friends. |
| B．they are common names for dogs. |
| C．they get along well with other dogs. |
| D．they have donated blood to other dogs. |
What do we know about the traveling vet lab?
| A．It is a Red Cross vehicle. |
| B．It collects dogs’ blood for other dogs. |
| C．It travels through Philadelphia every day. |
| D．It was donated by the University of Pennsylvania. |
What can we learn from Para.4?
| A．Sandy Lucas is unwilling to let her dog donate blood. |
| B．The bloodmobile welcomes dogs from anywhere in the city. |
| C．Penn Vet’s animal hospital in downtown Philadelphia is popular. |
| D．The animal bloodmobile has made it easier for dogs to donate blood. |
By writing the last paragraph, the author wants to ________.
| A．ask us to help dogs. |
| B．show the importance of dogs. |
| C．encourage us to donate blood. |
| D．compare humans with dogs. |
The following are a few cities with cheap attractions or restaurants in California, the US.
Cathedral City
The Indian Oven in the city will give you a high-quality dining experience. It’s a restaurant with traditional Indian dishes. All of the lunch specials are $5.95 and are served from 11:30 am to 2:00 pm. The windows of the restaurants give you the beautiful views of desert mountain scenes. You need to call 92234(760)770-3918 to book a table.
Palm Desert
Palm Desert, a city in Riverside County, has a number of free desert hiking trails(小径). They are named after famous Western Hollywood cowboys. The trails are fun to hike on. At some points they go up very high and you can get a bird’s-eye view of the surrounding desert cities. The paths are dusty, so bring some good hiking boots and hats. Do bring some water and your phone. It’s great for an afternoon hike after 2 pm. Call 92260(760)340-0574 or 92253(760)564-4712 to learn more.
Lake Cahuilla
Away from the busy streets of the city of Palm Springs, Lake Cahuilla is a great recreational(娱乐的) area you can visit in La Quinta. It is at the foot of the Santa Rosa Mountains. It costs $3.00 for per person to enter the area, but a half for kids under 7. The activities include: camping, fishing, bicycling, and horseback riding. If you want to save on rooms, you can stay in an RV. Call 92278(760)664-7215 and you’ll learn something else.The desert hiking trails__________.
| A．are named after some famous people |
| B．reach the top of some high mountains. |
| C．provide visitors with free water and food. |
| D．have attracted many well-known cowboys. |
If you want to know more about the restaurants in Lake Cahuilla, you can call __________.
| A．92260(760)340-0574 | B．92278(760)664-7215 |
| C．92234(760)770-3918 | D．92253(760)564-4712 |
We can learn from the passage that ________.
| A．the Indian Oven must be a well-known restaurant in India. |
| B．kids enjoy the hiking trails in Palm Desert at half price. |
| C．Palm Desert has been badly polluted by human activities. |
| D．staying in an RV costs less than staying in a hotel room. |
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