2018 年 06 月大学英语四级考试真题（第 1 套）

An office tower on Miller Street in Manchester is completely covered in solar panels. They are used to create some of the energy used by the insurance company inside. When the tower was first __26__ in 1962, it was covered with thin square stones. These small square stones became a problem for the building and continued to fall off the face for 40 years until a major renovation was __27__. During this renovation the building's owners, CIS, __28__ the solar panel company, Solar century. They agreed to cover the entire building in solar panels. In 2004, the completed CIS tower became Europe's largest __29__ of vertical solar panels. A vertical solar project on such a large __30__ has never been repeated since.

Covering a skyscraper with solar panels had never been done before, and the CIS tower was chosen as one of the "10 best green energy projects". For a long time after this renovation project, it was the tallest building in the United Kingdom, but it was __31__ overtaken by the Mill bank Tower.

Green buildings like this aren't __32__ cost-efficient for the investor, but it does produce much less pollution than that caused by energy __33__ through fossil fuels. As solar panels get __34__, the world is likely to see more skyscrapers covered in solar panels, collecting energy much like trees do. Imagine a world where building the tallest skyscraper wasn't a race of __35__, but rather one to collect the most solar energy.

Losing your ability to think and remember is pretty scary. We know the risk of dementia (痴 呆症) increases with age. But if you have memory slips, you probably needn't worry. There are pretty clear differences between signs of dementia and age-related memory loss.

After age 50, it's quite common to have trouble remembering the names of people, places and things quickly, says Dr. Kirk Daffner of Brigham and Women's Hospital in Boston.

The brain ages just like the rest of the body. Certain parts shrink, especially areas in the brain that are important to learning, memory and planning. Changes in brain cells can affect communication between different regions of the brain. And blood flow can be reduced as blood vessels narrow.

Forgetting the name of an actor in a favorite movie, for example, is nothing to worry about. But if you forget the plot of the movie or don't remember even seeing it, that's far more concerning, Daffner says.

When you forget entire experiences, he says, that's "a red flag that something more serious may be involved." Forgetting how to operate a familiar object like a microwave oven, or forgetting how to drive to the house of a friend you've visited many times before can also be signs of something going wrong.

But even then, Daffner says, people shouldn't panic. There are many things that can cause confusion and memory loss, including health problems like temporary stoppage of breathing during sleep, high blood pressure, or depression, as well as medications (药物) like antidepressants.

You don't have to figure this out on your own. Daffner suggests going to your doctor to check on medications, health problems and other issues that could be affecting memory. And the best defense against memory loss is to try to prevent it by building up your brain's cognitive (认知的) reserve, Daffner says.

"Read books, go to movies, take on new hobbies or activities that force one to think in novel ways," he says. In other words, keep your brain busy and working. And also get physically active, because exercise is a known brain booster.

A letter written by Charles Darwin in 1875 has been returned to the Smithsonian Institution Archives (档案馆) by the FBI after being stolen twice.

"We realized in the mid-1970s that it was missing," says Effie Kapsalis, head of the Smithsonian Institution Archives. "It was noted as missing and likely taken by an intern (实习生), from what the FBI is telling us. Word got out that it was missing when someone asked to see the letter for research purposes," and the intern put the letter back. "The intern likely took the letter again once nobody was watching it."

Decades passed. Finally, the FBI received a tip that the stolen document was located very close to Washington, D.C. Their art crime team recovered the letter but were unable to press charges because the time of limitations had ended. The FBI worked closely with the Archives to determine that the letter was both authentic and definitely Smithsonian's property.

The letter was written by Darwin to thank an American geologist, Dr. Ferdinand Vandeveer Hayden, for sending him copies of his research into the geology of the region that would become Yellowstone National Park.

The letter is in fairly good condition, in spite of being out of the care of trained museum staff for so long. "It was luckily in good shape," says Kapsalis, "and we just have to do some minor things in order to be able to unfold it. It has some glue on it that has colored it slightly, but nothing that will prevent us from using it. After it is repaired, we will take digital photos of it and that will be available online. One of our goals is to get items of high research value or interest to the public online."

It would now be difficult for an intern, visitor or a thief to steal a document like this. "Archiving practices have changed greatly since the 1970s," says Kapsalis, "and we keep our high value documents in a safe that I don't even have access to."