Have you ever dreamed about sending a letter to yourself or your friends in the future? While express mail(快递) is a fast way to send your letters, there is another type of mail appearing in China as a new business—future mail.

     “The letter should be sent next Mother's Day and not a day earlier!” Lin Xiaofan, acollege student in Shanghai, tells one of the companies offering the service.

Lin Xiao fan wrote the letter to her mother nearly a year earlier to express her love to hermother for next Mother's Day.

“Offering thisservice makes people slow down and lets them understand the meaning of ‘time'in another way,” said Zheng Zhimin, manager at a “future mail” company. Zheng thinks “future mail” letters help remind us of care, friendship and love.

      While “futuremail” is becoming more and more popular, some people are wondering what will happen if the postal address changes or if the company goes broken before theletters arrive.

     Zheng said customers are glad to sign a contract(签订合同) to make sure that they canbe compensated if their letters are lost or damaged.

    Most of the customers are college students and young white-collar(白领) workers. Psychologists (心理学家) said that young Chinese might have a new way to express their feelings through this service. Most peopleput their hopes and wishes in the letter so that they can experience the connection(联系) between the past and the present when they receive theletter.

    All over the world the need for more laptops and computers increases each year. Networks have been part of our life. Probably everyone with a portable device （移动设备）has once logged on to a public WiFi network without paying for it, while they are having a coffee, on a train, in a shopping mall or at a hotel. However, is this kind of public WiFi network safe?

    Some networks are better protected than others because encryption （加密）methods are used. Therefore, they are safer than others. But a survey in 2015 showed that more than 950 million records were not protected, including addresses, emails, birth dates, phone numbers, passwords and so on. These open WiFi networks are really not safe, because it is very easy for hackers （黑客） to break into the operating system and get people's private information.

    Most smartphones and laptops, by themselves, search and connect to WiFi networks. They usually prefer a network with a connection that has been used before. Hackers' devices are able to record these searches and look like the trusted WiFi networks. When these smartphones and laptops log on to the networks which are not real, hackers can easily steal their private information.

    So next time, when we want to use our laptops or our smartphones in public places which offer free WiFi networks, please think it twice or take safe measures before using them.

    It took 13 years of international effort to map the human biological blueprint of all the genes (基因) that make us different people. The first rough draft (草图) made in 2000. The last of our 23 chromosomes (染色体) was clearly described in 2006. Ever since then, the age of personal genetic testing has been upon us. Since that time, a growing number of private companies have come on the market mostly through the Internet, offering to scan your personal DNA and compare it to some disease markets of the blueprint, called DTC genetic tests.

    But over the last five years the medical world has been discussing excitedly about whether these DTC tests are helpful or harmful, scientifically believable or completely useless. One of the usual criticisms (批评) is that the science is so new that no one really knows yet how to explain the information.

    "At present they largely remain in the period of research studies," notes Dr. Greg Ferro, special advisor to the director of genomic medicine at the US National Human Genome Research Institute. Ferro says there are two reasons." The first is that when they offer a test, are they really checking what they should check? And then the next is that even if it is believable, does what the test is checking really mean anything to your health?"

    Other worries include the privacy of the results and how your personal genetic information might be used by insurance (保险) companies to refuse your insurance or your boss to dismiss you. Or you could learn information with a huge social or personal impact (冲击), such as finding out that genetically you cannot possibly be the father of your child. It can also give you risks that may break your life, such as whether you are at high risk of cancer, Parkinson or other terrible diseases.

    Criticisms over the tests are such that some countries, such as Germany, have banned them. In 2011, some scientists advised the US government that most tests should be done under the guidance of medical professionals (专家). The UK government also expressed its worries about DTC genetic tests and in August 2010 made a set of rules to guide the development of genetic tests.

    In 2011, three medical researchers published a review article in the International Journal of Clinical Practice, saying that such tests offered more risks than benefits. The most important reason is that the tests might create worries or unreal results or drive unnecessary medical treatments. They also noted some of the genetic information the tests are based on at present is far from being perfect.

    Cambodia (柬埔寨) is going to open the Angkor Wat temples (吴哥窟) at night to interest more tourists to the poor country.

    Tourism is an important foreign currency earner (外汇收入) for Cambodia. More than 1,000,000foreign people are going to visit it this year, and most of them are from South Korea, Japan and the United States. More than half of visitors will visit the Angkor Wat temples.

    Now visitors must walk out of Angkor Wat temples at sunset, but Cambodia is going to extend (延长) the visiting hours to as late as 8:30p. m.

    "We want visitors to see all views of the temples, even in the dark places where they may not see some of the sculptures and statues," Bun Narith said.

    But as hotels are more and more, people need lots of underground water. People say the uncontrolled pumping (无节制地抽水) of underground water is bad for the Earth under the temples.