No one is sure how the ancient Egyptians built the pyramids near Cairo. But a new study suggests they used a little rock‘n'roll. Long-ago builders could have attached wooden pole s to the stones and rolled then across the sand, the scientists say.
“Technically, I think what they're proposing is possible,” physicist Daniel Bonn said.
People have long puzzled over how the Egyptians moved such huge rocks. And there's no obvious answer. On average, each of the two million big stones weighed about as much as a large pickup truck. The Egyptians somehow moved the stone blocks to the pyramid site from about one kilometer away.
The most popular view is that Egyptian workers slid the blocks along smooth paths. Many scientists suspect workers first would have put the blocks on sleds(滑板). Then they would have dragged them along paths. To make the work easier, workers may have lubricated the paths either with wet clay or with the fat from cattle. Bonn has now tested this idea by building small sleds and dragging heavy objects over sand.
Evidence from the sand supports this idea. Researchers found small amounts of fat, as well as a large amount of stone and the remains of paths.

However, physicist Joseph West thinks there might have been a simpler way , who led the new study . West said , “I was inspired while watching a television program showing how sleds might have helped with pyramid construction . I thought , ‘Why don't they just try rolling the things?'“A square could be turned into a rough sort of wheel by attaching wooden poles to its sides , he realized . That , he notes , should make a block of stone” a lot easier to roll than a square”.
So he tried it.
He and his students tied some poles to each of four sides of a 30-kilogram stone block. That action turned the block into somewhat a wheel. Then they placed the block on the ground.
They wrapped one end of a rope around the block and pulled. The researchers found they could easily roll the block along different kinds of paths. They calculated that rolling the block required about as much force as moving it along a slippery(滑的)path.
West hasn't tested his idea on larger blocks, but he thinks rolling has clear advantages over sliding. At least, workers wouldn't have needed to carry cattle fat or water to smooth the paths.

    Recently, American President Trump announced his budget. One of the budgets would cut all funding to the Institute of Museum and Library services and libraries across the United States. However, as far as I'm concerned, we need to save our libraries.

    Libraries provide books and after-school programs for children. They encourage literacy (识字）with summer programs. They help inspire a life-time love of learning and reading in children of all ages. Without them, where will kids with no Internet at home do their homework? Where will kids have a place to study or borrow books after school? Therefore, we need libraries for our kids. We need them so that kids can grow up with a place, other than school, where learning and exploration is encouraged. For adults, libraries serve as a place where they can use the Internet to apply for jobs, get job training, early voting centers as well as book clubs to help make new friends. It can also serve as a place to pick up a book and learn something new. What's more，they can also borrow a book and get away from it all.

    Libraries save our information for the next generation. When we live in an age of alternative (选择性的）facts, where science is ignored in favor of personal feelings, we need libraries now more than ever. We need them to educate ourselves on the facts and hold the government responsible for them. We need them to have strong public participation(参与).

    If you agree with me，you shouldn't be silent on this issue. You can write or call directly to tell the president to save our libraries. You can also write to both your state Senators (参议员）and your district representative. If you do not know who they are, you can find out here. Let them know this is a beneficial issue because all people use public libraries in their daily life.

    Two of the saddest words in the English language are "if only". I live my life with the goal of never having to say those words, because they convey regret, lost opportunities, mistakes, and disappointment.

    My father is famous in our family for saying "Take the extra minute to do it right." I always try to live by the "extra minute" rule. When my children were young and likely to cause accidents, I always thought about what I could do to avoid an "if only" moment, whether it was something minor like moving a cup full of hot coffee away from the edge of a counter, or something that required a little more work such as taping padding (衬垫) onto the sharp corners of a glass coffee table.

    I don't only avoid those "if only" moments when it comes to safety. It's equally important to avoid "if only" in our personal relationships. We all know people who lost a loved one and regretted that they had foregone an opportunity to say "I love you" or "I forgive you." When my father announced he was going to the eye doctor across from my office on Good Friday, I told him that it was a holiday for my company and I wouldn't be here. But then I thought about the fact that he was 84 years old and I realized that I shouldn't give up an opportunity to see him. I called him and told him I had decided to go to work on my day off after all.

    I know there will still be occasions when I have to say "if only" about something, but my life is definitely better because of my policy of doing everything possible to avoid that eventuality. And even though it takes an extra minute to do something right, or it occasionally takes an hour or two in my busy schedule to make a personal connection, I know that I'm doing the right thing. I'm buying myself peace of mind and that's the best kind of insurance for my emotional well-being.

The Domestication （驯化）of Cats

    For centuries, the common view of how domestication had occurred was that prehistoric people, realizing how useful it would be to have animals kept for food, began catching wild animals and breeding （繁殖）them. Over time, by allowing only animals with "tame"（驯养）characteristics to produce their babies, human beings created animals that were less wild and more dependent upon people. Eventually this process led to the domestic farm animals and pets that we know today, having lost their ancient survival skills and natural abilities.

    Recent research suggests that this view of domestication is incomplete. Prehistoric human beings did catch and breed useful wild animals, but specialists in animal behavior now think that domestication was not simply something people did to animals—the animals played an active part in the process. Wolves and wild horses, for example, may have taken the first steps in their own domestication by hanging around human settlements, feeding on people's crops and getting used to human activity. The animals which were not too nervous or fearful to live near people produced their babies that also tolerated humans, making it easier for people to catch and breed them.

    In this version, people succeededin domesticating only animals that had already adapted easily to life around humans. Domestication required an animal that was willing to become domestic. The process was more like a dance with partners than a victory of humans over animals.

    At first glance, the laming of cats seems to fit nicely into this new story of domestication. A traditional theory says that after prehistoric people in Egypt invented agriculture and started farming, rats and mice gathered to feast on their stored grain. Wildcats, in tum, gathered at the same places to hunt and eat the rats and mice. Over time, cats got used to people and people got used to cats. Some studies of wildcats, however, seem to call this theory into question. Wildcats don't share hunting and feeding areas, and they don't live close to people. Experts do not know whether wildcats were partners in their own domestication. They do know that long after people had acquired domestic dogs, sheep and horses, they somehow acquired domestic cats. Gradually they produced animals with increasingly tame qualities.

Teaching Poetry

    No poem should ever be discussed or "analyzed", until it has been read aloud by someone, teacher or student. Better still, perhaps, is the practice of reading it twice, once at the beginning of the discussion and once at the end, so the sound of the poem is the last thing one hears of it.

    All discussions of poetry are, in fact, preparations for reading it aloud, and the reading of the poem is, finally, the most telling "interpretation" of it, suggesting tone, rhythm, and meaning all at once. Hearing a poet read the work in his or her own voice, on records or on film, is obviously a special reward. But even those aids to teaching can not replace the student and teacher reading it or, best of all, reciting it.

    I have come to think, in fact, that time spent reading a poem aloud is much more important than "analysing" it, if there isn't time for both. I think one of our goals as teachers of English is to have students love poetry. Poetry is "a criticism of life", and "a heightening of lief". It is "an approach to the truth of feeling", and it "can save your life". It also deserves a place in the teaching of language and literature more central than it presently occupies.

    I am not saying that every English teacher must teach poetry. Those who don't like it should not be forced to communicate this to anyone else. But those who do teach poetry must keep in mind a few things about its essential nature, about its sound as well as its sense, and they must make room in the classroom for hearing poetry as well as thinking about it.

Researchers believe they have found evidence for a hidden ocean on Mimas, one of Saturn's major moons. This makes Mimas a target for learning more about the origins of life in our solar system. 

Saturn has 146 moons orbiting it. The biggest is larger than the planet Mercury; the smallest is roughly the size of a sports field on the Earth. Mimas, which was first discovered in 1789, is one of the major moons and is about 250 miles wide. 

Experts used to think Mimas was mostly made out of solid ice and rock. In 2014, astronomers noticed its orbit around Saturn was moving unsteadily. A shaky orbit can be caused either by a core shaped like a rugby ball or a huge liquid ocean beneath the surface. At first, lots of astronomers argued against the suggestion that Mimas had an ocean because there is no sign of it on the surface. 

To investigate more thoroughly, researchers looked at images taken by Cassini, a NASA spacecraft sent to study Satun. The images showed that the moon's orbit around Saturn drifted by about six miles over 13 years. The team's calculations found that the only way Mimas could move in this way is if it had a hidden ocean under the surface. They think the ocean formed when the moon's core warmed up and melted some of the ice. 

Mimas is just one of many moons that scientists think could have oceans below the surface Ganymede, which orbits Jupiter and is the largest moon in the solar system, has more water in its ocean than all of the oceans on the Earth. Titan, another of Saturn's moons, is believed to have a salty ocean beneath the surface. 

Space agencies want to study these oceans because they might be home to living organisms. However, the ocean on Mimas might not be old enough for life to have emerged there yet. It took hundreds of millions of years for life to develop on the Earth and the ocean on Mimas is relatively young;it is less than 25 million years old.