See a cellphone cover that you like on Taobao? Forget about placing an order, paying the bill online and waiting for days for it to be delivered to you. In the near future, you'll be able to get it in minutes just by hitting “print” on your computer.

    You might find it hard to believe that you could actually “print” an object like you would a picture. But it is not that hard to understand how it would work. Just as a traditional printer sprays ink onto paper line by line, modern 3D printers spread material onto a surface layer by layer, from the bottom to the top, gradually building up a shape.

    Instead of ink, the materials the 3D printer uses are mainly plastic, resin(树脂) and certain metals. The thinner each layer is—from a millimetre to less than the width of a hair—the smoother and finer the object will be.

    This may sound like a completely new technology, but the truth is that 3D printing has been around since the late 1980s. Back then, it was barely affordable for most people, so few knew about it.

    Last year, though, saw a big change in the 3D printing industry—printers became much cheaper. For example, 10 years ago a desktop 3D printer might have cost ￡20，000, while now they cost only about ￡1，000, according to the BBC.

    Taken out of the factory and introduced to more diverse and common uses, 3D printing can create just about anything you can think of—flutes , bikinis, jewelry, aircraft parts and even human organs. In fact, scientists from Cornell University in New York have just made an artificial ear using a 3D printer, according to Science Daily. The fake ear looks and acts exactly like a natural one.

    However, as 3D printing becomes more common, it may bring about certain problems—such as piracy. “Once you can download a coffee maker, or print out a new set of kitchen utensils (餐具) on your personal 3D printer, who will visit a retail  store again？” an expert in 3D printing told Forbes News. Even more frightening, what if anyone in the world could use a 3D printer to print out a fully functioning gun?

    For many years, scholars have regarded My Mortal Enemy as somewhat of an enigma. Written in only a few months during the early spring of 1925 and published in 1926, Willa Cather's shortest novel was sandwiched in between The Professor's House (1925) and Death Comes for the Archbishop (1927). While the subject matter of these latter two works can be traced to Cather's experience in the desert Southwest, My Mortal Enemy seemingly has nothing to do with these subjects or her Nebraska roots; it appears to have come out of nowhere, puzzling those who have tried to fit this rather irregular work into a logical progression of Cather's artistic development. The question of what caused Cather to write such a novel at this point in her career, for example, has still not been answered definitively. One commonly held hypothesis (假说) was first voiced by Marcus Klein, who in his 1961 introduction to the novel wrote that for Cather, “The story of Myra Henshawe must have been a personal crisis”. Klein, though, acknowledged that he could not prove his theory, “because there is available no record other than the novel”. Emmy Stark Zitter has recently argued that in My Mortal Enemy and Sapphira and the Slave Girl(1940) Cather exercises the autobiographical impulse (冲击) by putting details of her own life into her fiction, but, like Klein, she is unable to name which “details” of her life Cather drew on in writing My Mortal Enemy.

    As hinted (暗示) in the above statements by Klein and Zitter, much of the general uncertainty about the meaning of My Mortal Enemy can be traced to the absence of a persuasive theory as to who the real-life models for the novel's characters were and what Cather's relationship to them was. Cather herself wrote in a 1940 letter that, in James Woodress's paraphrase, “she had known Myra's real-life model very well, and the portrait drawn in the story was much as she remembered her”; Cather also added that the woman had died fifteen years before My Mortal Enemy was published, and that many relatives of this model later wrote to her to say that they recognized the “real” Myra from her description in the novel. Given such hints and Cather's liking for drawing on her experiences in Nebraska for characters, settings, and plots, it is quite understandable that scholars have thus looked to Red Cloud and Lincoln for possible sources of the people and events depicted in My Mortal Enemy.

    In light of the evidence presented in this article, though, I believe that Cather intended her comments about the model for Myra Henshawe to serve as red herrings (转移注意力的言语) that would protect her relationship with the couple who were the prototypes (原型) for the Henshawes, both of whom were still alive in 1925. Mark Madigan has recently confirmed how Cather in 1905 had to hold off publishing “The Profile (传略)” because of fears that the main character might recognize herself and commit suicide, and twenty years later Cather would have been well aware of how her description of the Henshawes might have affected both the real-life wife (who died in 1929) and husband (who died in 1949) if they had recognized themselves. It is my argument that the Henshawes were modeled after people Cather knew not in Nebraska but rather in New York: S. S. and Hattie McClure. Myra's uncle, John Driscoll, was modeled after Hattie's father, Professor Albert Hurd.

    Possibly most important, identifying the Henshawes as the McClures allows us to more conclusively identify Cather herself with Nellie Birdseye. Nellie and Cather, both Midwestern onlookers and recorders, experienced four distinct stages in their relationships with the Henshawes and the McClures (especially with S. S.) My Mortal Enemy, I believe, was an extended attempt by Cather to deal with certain aspects of her own past and to move on in a world stripped of romantic illusion.

    My friend Susan has a huge-hearted husband. He is once again on the front lines of fighting the fires in Northern CA. As a Chief Battalion leader, his job is very dangerous and his time away from his family is often for weeks at a time during "fire season".

Every time before he leaves, Ethan, Susan and each of the three teens hold one another and thoughtfully each shares the best of their traditions — each promises to do the tasks that will keep the family a well-oiled machine while Ethan is away.

    Ethan has brought back animals that lost their homes in the fires. By now, a gray rabbit, two parrots and a small group of Nubian goats have been added into the family.

    When Ethan is on duty, Susan keeps checking her cell phone for Ethan's text messages. His substantial (大量的) white facial hair is often mistaken for that of Father Christmas by children who are carried out of their burning homes by him.

    For each rescued child, a toy bear is waiting to be matched with him/her. For each adult, Ethan provides clean clothes. He finds pleasure in doing his job well. He is grateful to be often on the front line with frightened people and their poor pets.

    I am mentioning Ethan because by now the big fire has been spreading widely for a week. It has caused 55 deaths and left 500,000 people homeless. Now I am here at my school site, and the smoky air is keeping our students inside, waiting for rescue.

    Ninety years ago a man named Howard Carter made a great find. But he didn't discover an unknown people group or a new plant. He found the resting place of a king.

    People had seen signs of King Tutankhamun's tomb (坟墓) but had never found it. Finally, Carter's team discovered a set of steps that led down to some underground rooms. There Carter found the king's body and many of his treasures.

    Carter recorded his first impression in his popular book, The Tomb of Tut-Ankh-Amen：

At first I could see nothing, the hot air coming from the room causing the candle light to flicker (闪烁), but later, as my eyes grew used to the light, details of the room within appeared slowly and clearly, strange animals and gold—everywhere the light of gold... I was struck speechless with amazement, and when Lord Carnarvon, unable to stand the silence any longer, asked anxiously,  “Can you see anything?” it was all I could do to get out the words, “Yes, wonderful things.”

    The discovery has made King Tutankhamun, Tut for short, one of the best-remembered kings of Egypt. Tut became king when he was only 9 years old and ruled ancient Egypt from 1332 to 1323 B.C. No one is sure why, but he died suddenly before he turned 20. Because he died so young, there wasn't time to prepare a great tomb for him. So he ended up with a smaller tomb. Its small size was actually the reason why it stayed hidden for so long. And, Tut's tomb was not like other Egyptian kings'—it was not as damaged by time or robbers as other tombs. King Tut's tomb remains the best-kept royal (皇室的) tomb ever discovered. The discovery of this little tomb has helped people learn a great deal about ancient Egypt.

    “An apple a day keeps the doctor away.” Similarly, if we drink a little more water every day, we may find that we need to go to the doctor a lot less often. A healthy diet is made up of water and a great many different kinds of foods. We know that healthy foods like fruits, vegetables and fish, are important as they provide us with energy and fiber, without giving us too much fat and sugar. But why is water important?

    The human body needs water to survive. Water is important as it carries poisons and waste out of our bodies. So, doctors advise us to drink plenty of water, much more than the small amount we need to stay alive.

    Some doctors believe that water is important for our health in all kinds of ways. They believe that a great many illnesses and health problems start as a result of dehydration(脱水)—a lack of water in the body. Most people are dehydrated at least some of time, although they probably don't know it. It is surprising to learn that if we feel thirsty, we are already in the first stage of dehydration. In fact, we are advised to drink water before we feel thirsty.

    These doctors think that health problems such as headaches, high blood pressure and asthma(哮喘) could be helped if people drink more water. They also believe that drinking more water can help people who are overweight. Water contains no calories so it will not make us put on weight. If we drink water, we will probably drink less sugary soft drinks such as Coca-cola. Doctors also believe that drinking more water may stop people from overeating. They say that many people think that they are hungry when they are, in fact, thirsty. Doctors suggest, therefore, that we eat less food and drink more water. There are still many health problems that cannot be solved by drinking water, so we should not stop going to seeing the doctor completely. However, if we make a decision to drink water every day, we may find that we need to go to the doctor a lot less often.

    Over the years, cheerleading has taken two primary forms: game-time cheerleading and competitive cheerleading. Game-time cheerleaders' main goal is to entertain the crowd and lead them with team cheers, which should not be considered a sport. However, competitive cheerleading is more than a form of entertainment. It is really a competitive sport.

    Competitive cheerleading includes lots of physical activity. The majority of the teams require a certain level of tumbling (翻腾) ability. It's a very common thing for gymnasts, so it's easy for them to go into competitive cheerleading. Usually these cheerleaders integrate lots of their gymnastics experience including their jumps, tumbling, and overall energy. They also perform lifts and throws. This is where the "fliers" are thrown in the air, held by "bases" in different positions that require strength and working with other teammates.

    Competitive cheerleading is also an activity that is governed by rules under which a winner can be declared. It is awarded points for technique, creativity and sharpness. Usually the more difficult the action is, the better the score is. That's why cheerleaders are trying to experience great difficulty in their performance.

    Besides, there is also a strict rule of time. The whole performance has to be completed in less than three minutes and fifteen seconds, during which the cheerleaders are required to stay within a certain area. Any performance beyond the limit of time is invalid.

    Another reason for the fact that competitive cheerleading is one of the hardest sports is that it has more reported injuries. According to some research, competitive cheerleading is the number one cause of serious sports injuries to women. Emergency room visits for it are five times the number than for any other sport, partially because cheerleaders don't use protective equipment. Smiling cheerleaders are thrown into the air and move down into the arms of the teammates, which may easily cause injuries. Generally, these injuries affect all areas of the body, including wrists, shoulders, ankles, head, and neck.

    There can be no doubt that competitive cheerleading is a sport with professional skills. Hopefully, it will appear in the Olympics since cheerleaders are just as athletic and physically fit as those involved in the more accepted sports. It should be noted that it is a team sport and even the smallest mistake made by one teammate can bring the score of the entire team down. So without working together to achieve the goal, first place is out of reach.