Most buildings are built to stand up straight, but these look as if they might fall over!

The church tower of Suurhusen

    Built in 1450, the 27-meter-high church tower lies in Suurhusen, Germany. It was built in wet land on foundations of oak tree trunks (树干). When the land was drained (排水) later, the wood broke down, causing one side of the tower to be a little lower than the other. In 1975, the tower became a real hazard and people were not allowed to enter until the foundations were made strong again. The lean (倾斜) of the tower is now about five degrees.

The Leaning Tower of Pisa

    The work of building the tower began in 1173, and was finally completed in 1372. In fact, it began to lean after just a couple of floors were built. And this condition continued in the centuries after its completion. The tower was finally closed to the public in 1990 after people failed to stabilize (使稳固) its foundations. In 2001, it was reopened after engineers removed soil from underneath its raised side. Now it leans just an angle of 3.97 degrees.

Capital Gate of Abu Dhabi

    Completed in 2011, the Capital Gate tower in Abu Dhabi was designed to lean eighteen degrees. The building stands next to the Abu Dhabi National Exhibition Centre and contains, among other things, a fine hotel with wonderful views of the harbour. Also known as the leaning tower of Abu Dhabi, the tower is one of the tallest buildings in the city.

Big Ben of London

    The building leans 0.26 degrees to the northwest. This is mainly caused by the engineering projects that have been carried out in the ground below it since the late 1800s. The tower, which has been continuously open since it was completed in 1858, has nowhere near the lean of the Tower of Pisa and is still completely safe to enter.

    Were dinosaurs (恐龙) warm-blooded or cold-blooded? According to a new study, scientists have found that they were somewhere in the middle. This new study shows that dinosaurs were very different from most of today's animals that are either warm or cold-blooded.

    “I think we were all surprised by this,” said Felisa Smith from the University of New Mexico. “The idea certainly took some getting used to.”

    A study by a team of scientists led by John M. Grady of the university studied many different kinds of dinosaurs in their research. They looked at growth rate (比率), body temperature and body size of different kinds of dinosaurs.

    How are warm-blooded animals different from cold-blooded animals? Warm-blooded animals like humans can control their body temperature. They eat a lot, and burn calories (卡路里) quickly. They have a more active lifestyle than cold-blooded animals. While cold-blooded animals such as snakes do not control their body temperature. Instead, they must use sunlight to keep warm, and they move much more slowly. Cold-blooded animals do not need to eat very much. Their bodies slow down in colder temperatures.

    Besides dinosaurs, there are other animals that are not completely warm-blooded or cold-blooded, such as great white sharks.

    With all the traditional media channels, including newspapers, magazines and television shows, shrinking, advertisers are worrying about how they can reach customers. Banners(横幅) ads on our devices are ugly and disturbing. To overcome various digital problems, the ad industry has been serving up a sneaky(不光明正大的) solution: make ads look less like ads and more like the articles, videos and posts around them.

    This trend, called native advertising, has taken over the Internet; even the websites such as NYTimes.com and Wall-Street.com are using it. On Facebook and Twitter, every 10th item or so is an ad; only the small subtitle “Sponsored（赞助）” appearing in light gray type tells you which posts are ads.

    Won't dressing up ads to make them look like reported articles mislead people? Sometimes, yes. An Interactive Advertising Bureau study found that only 41 percent of general news readers could tell such ads apart from real news stories. And it's getting worse. Advertisers worry that the “Sponsored” label discourages readers from clicking, so some websites are making the labels smaller and less noticeable. Sometimes the labels disappear entirely.

    At a recent talk about the difficulty of advertising in the new, small-screen world, I heard an ad manager tell an impressive story. She had gotten a musical performance – paid for by her soft drink client- perfectly inserted（插入）into a TV awards show, without any moment of blackness before or after. “It looked just like part of the real broadcast!” she recounted happily.

    Look, it is great that native advertising works. But if advertisers truly believe in their material, they should have no problem labeling it as advertising.

    For now native ads continue to be a fashion- with no laws governing them and no labeling standard. But that could change; the Federal Trade Commission has begun considering regulation. If the new generation of digital advertisers clean up their act according to the regulation, native ads might become more acceptable.

    Started in 1636, Harvard University is the oldest of all the many colleges and universities in the United States. Yale, Princeton, Columbia and Dartmouth were opened soon after Harvard.

    In the early years, these schools were much alike. Only young men went to colleges. All the students studied the same subjects, and everyone learned Latin, Greek and Hebrew. Little was known about science then, and one kind of school could teach everything that was known about the world. When the students graduated, most of them become ministers or teachers.

    In 1782, Harvard started a medical school for young men who wanted to become doctors. Later, lawyers could receive their training in Harvard's law school. In 1825, besides Latin and Greek, Harvard began teaching modern languages, such as French and German. Soon it began teaching American history.

    As knowledge increased, Harvard and other colleges began to teach many new subjects. Students were allowed to choose the subjects that interested them.

    Today there are many different kinds of colleges and universities. Most of them are made up of smaller schools that deal with special fields of learning. There's so much to learn that one kind of school can' offer it all.

    Have you ever wondered what the longest word in the English language is? Believe it or not, there's no simple answer to the question. You might think it would be as easy as opening a dictionary and looking for the longest word. However, it's far more complicated (复杂的) than that.

    Over time, many people have suggested many different words for the title of the longest word in English. How can that be? That's because the first thing that people have different opinions on is what should be considered a word. Some of the words were simply made up to be the longest! For example, there is one really famous long word that most kids know. It comes from Disney's movie Mary Poppins: supercalifragilisticexpialidocious, which means wonderful. But since that 34-letter word was made up simply to be sung as a song in a movie, should it count?

    How about long words that actually describe something in the world? Scientists have come up with several possible choices. The name of a virus(病毒) totals 1,185 letters. There's also a protein(蛋白质) whose name totals 1, 909 letters. Should these win the title? "Not so fast!" say some people. Are these words ever actually used? Can they even be pronounced? And are they meaningful just because they are made up to be long?

    If you're wondering about some long words in common English, here are some examples. Those words include uncharacteristically (20 letters), deinstitutionalization(22 letters) and counterrevolutionaries (also 22 letters) Or perhaps the word "smiles" is the longest word in English. Sure, it has only six letters, but there is a "mile between the first and the last letters!

    Living in a foreign culture can be exciting, but it can also be confusing(令人迷惑的). A group of Americans who taught English in other countries recently discussed their experiences. They found that miscommunication was always possible, even over something as simple as "yes" and "no".

    On her first day in Micronesia, an island in the Pacific, Lisa thought people weren't paying any attention to her. The day was hot. She went into a store and asked, "Do you have cold drinks？" The woman there didn't say anything. Lisa repeated the question. Still the woman said nothing. She later learned that the woman had answered her: She had raised her eyebrows(眉毛), which in Micronesia means "yes".

    Jan remembered an experience she had in Bulgaria, a country in Europe. She went to a restaurant that was famous for its cabbage. She asked the waiter, "Do you have cabbage today？" He nodded his head. Jan waited, but the cabbage never came. In that country, a nod means "no".

    Tom had a similar problem when he arrived in India. After explaining something in class, he asked his students if they understood. They answered with many different nods and shakes of the head. He thought some people had not understood, so he explained again. When he asked again, they did the same thing. He soon found out that his students did understand. In India, people nod and shake their heads in different ways depending on where they come from. You have to know where a person is from to understand whether they mean "yes" or "no"．