Have you ever wanted to travel back in time? What about traveling into the future? There's an easy way to do it. One way you can make a time travel journey is by writing a letter to your future self to be opened in the future. To your future self, the letter will be a visit from the past. 

    What can be gained by writing a letter to yourself? Depends on how good your letter is. You have the chance to say something to your future self. What would you want to say? You'll be able to talk to yourself 5,10,15 years down the road. There may be instructions for your future self, or you may have goals that you will want to reach.

    There are a lot of things you could include in your letter or letters to yourself. The more you include, the better the letter will be to you. Be creative with what you put in your letter. Include a picture of yourself or family to show the period from which the letter came.

    You can store your letter in many different ways. You can give your letter to a friend or family member to keep and mail to you. If you can get others to take part, have them write letters to themselves as well and ask someone to be the letter holder until it's time to send the letters. You can also use a service online to store your letter and e-mail it to you. Ready to write to yourself two and a half years down the road?

    A warm drink of milk before bed has long been the best choice for those wanting a good night's sleep. But now a study has found it really does help people nod off（打瞌睡）—if it is milked from a cow at night.

    Researchers have discovered that “night milk” contains more melatonin(褪黑激素), which has been proven to help people feel sleepy and reduce anxiety（焦虑）.The study, by researchers from Seoul, South Korea, involved mice being fed with dried milk powder（奶粉） made from cows milked both during the day and at night. Those given night milk, which contained 10 times the amount of melatonin, were less active and less anxious than those fed with the milk collected during daytime, according to the study published in The Journal of Medicinal Food.

    Night milk quickened the start of sleep and caused the mice to sleep longer.

    While the effect of cow milk harvested at different time has not been tested on humans up to now, taking melatonin drugs has been suggested to those who have trouble falling asleep at night.

    Previous （以前的）studies have also showed that milk can be excellent for helping sleep because of the calcium content, which helps people to relax.

    Many people all over the world enjoy an alcoholic drink, such as wine or beer, during dinner. Many people raise a glass of alcohol to celebrate a wedding or a birthday. And having drinks after work with friends and co-workers is called "happy hour".

    All these situations are considered "social drinking" because they happen at social events. But when does "social drinking" become problem drinking?

    According to the World Health Organization alcohol abuse kills 3.3 million people each year. That is six percent of all deaths around the world. And in a new report on alcohol use around the world, the WHO says alcohol can create dependency, or addiction, in some people. The report also warns that alcohol use can increase the risk of developing more than 200 diseases, including some kinds of cancers. And, the WHO says alcohol abuse can put people at greater risk of infectious diseases, such as tuberculosis(肺结核), pneumonia (肺炎)and HIV.

    WHO Mental Health and Substance Abuse Director Shekhar Saxena says the organization is concerned about drinking among young people between the ages 15 and 19. And it is most concerned about "binge-drinking", or an extended period of heavy drinking.

    The report concludes that worldwide 16 percent of drinkers over the age of 15 engage in binge-drinking, which is much more harmful than other kind of drinking and causes the most harm in terms of accidents, self-harm and harm to others. High income countries have the highest alcohol consumption and also the highest prevalence(盛行) of binge-drinking.

    The report also found that the highest rates of alcohol-linked deaths are in Europe, followed by the West Pacific and then the Americans. The report also finds Europe is the area with the highest alcohol use. Central and Eastern Europe are especially high.

    The World Health Organization suggests ways countries can protect people from alcohol abuse. These include increasing taxes on alcohol sales, raising the drinking age limit, and controlling the marketing of alcoholic beverages.

    As scientists in the Netherlands tried to figure out how to build a super flying robot, they learned from one of nature s flyers: the humble fruit fly(果蝇).And by building this robot, they've gained new insights into how the fly carries out one of its dangerous tasks.

    The robot is called the DelFly Nimble Its wingspan(冀展)is about a foot wide. It has four wings that can beat at 17 times per second, which appear very delicate because they're made of the same material as space blankets.

    In the previous designs, they always had a tail, like a traditional airplane tail, said the robots main designer Matej Karasek. He's based at the Micro Air Vehicle Laboratory at Delft University of Technology in the Netherlands, and he and his colleagues published their findings on Thursday in Science

    “In the previous generations", he said, "flapping wings drove the robot forward while the tail helped to guide and stabilize it. But now the DelFly Nimble is completely controlled by the wings. The challenge then was actually combine the control into the wing movement, and that's what we achieved, Karasek said

    In the latest generation. the wings can each move individually or rotate(旋转)around the body of the robot in order to maximize the machine s agility(灵活 ) The robot can remain in one place in the air for about five minutes on a full battery or fly for more than a kilometer"， Karasek said, "And because the scientists are controlling all the movements, they can use the robot to learn more about how fruit flies actually carry out their dangerous tasks, which has caught the attention of biologists.”

    You've probably heard such reports. The number of college students majoring in the humanities (人文学科) is decreasing quickly. The news has caused a flood of high-minded essays criticizing the development as a symbol of American decline.

    The bright side is this: The destruction of the humanities is, finally, coming to an end. No more will literature, as part of an academic curriculum, put out the light of literature. No longer will the reading of, say, "King Lear" or D.H. Lawrence's "Women in Love" result in the annoying stuff of multiple-choice quizzes, exam essays and homework assignments.

    The discouraging fact is that for every college professor who made Shakespeare or Lawrence come alive for the lucky few, there were countless others who made the reading of literary masterpieces seem like two hours in the dentist's chair.

    The remarkably insignificant fact that, a half-century ago, 14% of the undergraduate population majored in the humanities (mostly in literature, but also in art, philosophy, history, classics and religion) as opposed to 7% today has given rise to serious reflections on the nature and purpose of an education in the liberal arts.

    Such reflections always come to the same conclusion: We are told that the lack of a formal education, mostly in literature, leads to numerous harmful personal conditions, such as the inability to think critically, to write clearly, to be curious about other people and places, to engage with great literature after graduation, to recognize truth, beauty and goodness.

    Literature changed my life long before I began to study it in college. Books took me far from myself into experiences that had nothing to do with my life, yet spoke to my life. But once in the college classroom, this precious, alternate life inside me got thrown back into that dimension of my existence that bored me. Homer, Chekhov and Yeats were reduced to right and wrong answers, clear-cut themes and clever interpretations. If there is anything to worry about, it should be the disappearance of what used to be an important part of every high-school education: the literature survey course, where books were not academically taught but thoroughly introduced—an experience unaffected by stupid commentary and useless testing.

    The literary classics are places of quiet, useless stillness in a world that despises (鄙视) any activity that is not profitable or productive. Literature is too sacred to be taught. It needs only to be read.

    Soon, if all goes well and literature at last disappears from the undergraduate curriculum—my fingers are crossed—increasing numbers of people will be able to say that reading the literary masterworks of the past outside the college classroom, simply in the course of living, was, in fact, their college classroom.