Grey clouds move as low as smoke over the treetops at Lolo Pass. The ground is white. The day is June 10.It has been snowing for the past four days in the Bitterroot Mountains.Wayne Fairchild is getting worried about our trek over the Lolo Trail-95 miles from Lolo Montana to Weippe in Idaho, across the roughest country in the West. Lewis and Clark were nearly defeated 200 years ago by snowstorms on the Lolo.Today Fairchild is nervously checking the weather reports.He has agreed to take me across the toughest,middle section of the trail.

    When Lewis climbed on top of Lemhi Pass,140 miles south of Missoula,on Aug.12,1805,he was astonished by what was in front of him;“high mountain chains still to the West of us with their tops partially covered with snow.”Nobody in what was then the US knew the Rocky Mountains existed,with peaks twice as high as anything in the Appalachians back East.

    Today their pathway through those mountains holds more attraction than any other ground over which they traveled,for its raw wilderness is an evidence to the character of two cultures:the explorers who braved its hardships and the Native Americans who prize and conserve the path as a sacred (神圣的)gift. It remains today the same condition as when Lewis and Clark walked it.

    The Lolo is passable only from July to mid-September.Our luck is holding with the weather,although the snow keeps getting deeper.As we climb to Indian Post Office,the highest point on the trail at 7,033 ft,we have covered 13 miles in soft snow,and we hardly have enough energy to make dinner.After a meal of chicken,I sit on a rock on top of the ridge (山脊）.There is no light visible in any direction,not even another campfire.For four days we do not see another human being.We are occupied with the things that mix fear with joy.In our imagination we have finally caught up with Lewis and Clark.

    In the last few years the popularity of eBooks has exploded．The advantages are clear：You can carry as many books with you as you want．You can simply download every book you like and instantly start reading instead of having to wait for the book to arrive by mail．

    However，one thing hadn't changed．If you wanted to rent a book you were still forced to use hardcopy books．Until now that is, Amazon．com recently announced the start of a new program where you can rent eBooks．

Where to rent eBooks？

    As mentioned before，Amazon．com is the first and currently the only retailer (零售商) that has a program in place for renting eBooks． Luckily，Amazon is the largest online retailer in the world and their eBook assortment (分类) is massive．They are also the producer of the Kindle，the most popular Reader，which means you can be sure that the eBooks you rent will work．

You can currently only rent Textbooks．But this is likely to change as soon as word gets out that you can save money by renting eBooks.

Why rent eBooks at Amazon?

* Save money：Save up to 80% of the normal price of the eBook．

* Decide how long you rent：From 30 days to 360 days，you decide how long you want it．You can extend the time by as little as a day．Or simply buy the eBook if you want to keep it after all．

*Use any device：If you rent an eBook from Amazon，you can read it on your PC，Mac，iPad，iPhone，Android device，Windows Phone 7．Blackberry．or Kindle．

* Keep your notes：Do you like to keep annotations (注释) and highlights in your eBooks？Don't worry．You can always revisit your notes and highlights through Amazon．com．

How to rent eBooks？

    Simply search for the eBook you want to rent on Amazon．com and select the "Rent eBooks" option. After that，a new page will open where you can select how long you'd like to rent the eBook．You can read eBooks for a period of 30 to 360 days．

    You decide how long you need the eBook．If you later find out you need it for longer, you can simply extend the time．Or buy it for the normal price whenever you want.

    Once you've chosen the time you want to rent the eBook，you simply go to checkout．Or you can use the "Rent now" button．

    To American visitors, Iceland is a very interesting country, partly because it is different in so many ways from he or she is used to seeing at home. There are quite a few things that are not done, or that do not exist on the island—quite a few “No's”．

    There is no pollution, for instance, no dogs are permitted in Reykjavik, the capital. There is no television on Thursdays or during the whole month of July, and only three hours of black­and­-white TV the rest of the time. There is no hard liquor（酒） on Wednesdays and no beer at any time. There is no handguns; only one prison of thirty­ five rooms in the whole land—an admirable figure, even for a small country of 313,376 people.

    There is no army, air force or navy. There is no tipping（给小费） for anything. There are no large stores open on Saturdays or Sundays. Since Iceland is located just under the Arctic Circle, there is no darkness in summer and no daylight in winter. But thanks to Gulf Stream, the climate is rather mild, with temperatures between 34 degrees and 52 degrees in July.

    The rules on television liquor and guns are the result of government decisions. But the absence of pollution is because of in great part the fact that Iceland gets its power from the thousands of hot springs(泉水) that come out of the ground. They provide all the energy needed by the country. In fact, Iceland uses only 3 percent of all its available power.

    Iceland has been described as a democratic（民主的） independent country where more fish are caught and more books published per person than anywhere else in the world. The Icelanders have always felt a particular love for literature. They wrote their first books in the ninth and tenth centuries AD. These works were poems and tales about the kings, heroes, and heroines of Iceland and Norway. At first, the stories were remembered and passed from generation to generation. They were finally written down between 1140 and 1220. The Icelanders have never stopped writing ever since. “Rather shoeless than bookless，” they proudly say.

阅读下列短文，从每题所给的四个选项 （A 、B 、C  和 D ）中，选出最佳选项。

    In an ideal world, people would not test medicines on animals. Such experiments are stressful and sometimes painful for animals, and expensive and time-consuming for people. Yet animal experimentation is still needed to help bridge vast gaps in medical knowledge. That is why there are some 50 to 100 million animals used in research around the world each year.

    Europe, on the whole, has the world's most restrictive (严格的) laws on animal experiments. Even so，its scientists use some 12 million animals a year, most of them mice and rats, for medical research. Official statistics show that just 1.1 million animals are used in research in America each year. But that is misleading. The American authorities do not think mice and rats are worth counting and, as these are the most common laboratory animals, the true figure is much higher. Japan and China have even less comprehensive (全面的) data than America.

    Now Europe is reforming the rules governing animal experiments by restricting the number of animals used in labs. Alternatives to animal testing，such as using human tissue or computer models, are now strongly recommended. In addition, sharing all research results freely should help to reduce the number of animals for scientific use. At present, scientists often share only the results of successful experiments. If their findings do not fit the hypothesis (假设) being tested, the work never sees the light of day. This practice means wasting time, money, and animals' lives in endlessly repeating the failed experiments.

    Animal experimentation has taught humanity a great deal and saved countless lives. It needs to continue，even if that means animals sometimes suffer. Europe's new measures should eventually both reduce the number of animals used in experiments and improve the way in which scientific research is conducted.

    Back in 1969, it was the Apollo 11 crew who flew to the moon in a spaceship. When U.S. astronauts Neil Armstrong and Edwin “Buzz” Aldrin stepped foot on the moon, they were the first. Meanwhile, their fellow astronaut Michael Coilins circled the moon in their spaceship, named Columbia.

    When Armstrong and Aldrin were done with their walk，they returned to the command module, and back to Earth. That part of the spaceship is on view at the Smithsonian's Air and Space Museum in Washington, D.C. But, if you cannot get to Washington，soon you will be able to see Columbia on your computer or your smartphone.

    Digital scientists are scanning the inside of the spaceship. They are creating an online model, in three dimensions, or“3 D”. By looking at these photographs, you will be able to see outer space，the way the astronauts did. It will be like sitting in their seats.

    Want your very own Columbia spaceship? You will be able to print a 3D copy of Columbia. Experts say anyone can make a life-sized model. But they expect most people to make smaller models of the 320×400 cm(11'X 13')command module.

    Scientists are using special 3D technology to scan the inside. They use cameras on long arms to take the photographs. The thousands of photographs taken will be combined with 50 laser scans.

    What would it be like to sit inside Columbia and take a look around? All the images will be loaded into software that allows you to look around the module on a computer screen. The user will be able to see the Columbia both inside and out. The Smithsonian says that the 3D technology gives the user ways to see things they cannot see at the museum. And it will give information that even the museum curators(馆长)have not seen before.

    “With the Command Module, no one has been inside since it came into the collection,” says Adam Metallo. Smithsonian 3D imaging specialist. “Now the information we capture can give anyone in the world a view of what it looks like inside this incredible piece of history.”

    Every time your fingers touch your cell phone, they leave behind trace of amounts of chemicals. And each chemical offers clues to you and your activities. By studying them, scientists might be able to piece together a story about your recent life, a new study finds.

    A molecule (分子) is a group of atoms. It is the smallest amounts of some chemicals. Your skin is covered in molecules picked up by everything you touched. With each new thing your skin contacts, you leave behind some small share of what it'd touched earlier.

    Researchers at the University of California, San Diego (UCSD) recently studied such chemical leftovers on the phones of 39 volunteers. The study was led by biochemist Amina Bouslimani. To explore those residues (剩余物), the UCSD team wiped the surface of each volunteer's phone with a cotton swab (药签). The scientists also swabbed each person's right hand. Then the researchers compared the chemicals found on each cell phone.

    The scientists discovered as many of the molecules as they could. They then compared those to a database of chemicals. Pieter Dorrestein, a UCSD pharmaceutical chemist, had helped set up that database a few years earlier, which contains various substances, including spices, caffeine and medicines.

    Traces of everything from hundreds to thousands of different molecules turned up on each phone. The molecules suggested what had been in the body, and what each person had handled before touching the phone. From all these molecules, Bouslimani says, “We could tell if a person is likely female, uses high-end cosmetics (化妆品), colors her hair, drinks coffee, prefers beer over wine or likes spicy food.”

    Police already use molecular analyses to look for traces of explosives or illegal drugs. To date, Dorrestein says, he's never heard of police using phone residues to narrow down behaviour clues to search for a suspect. But detectives might one day use such data to track down someone who left a phone behind at a crime scene.