Think about vitamin D when you're catching up on summer rays. It's sometimes called the “sunshine vitamin” because it's produced in your skin in response to sunlight. Vitamin D is a fat-soluble (脂溶性的) vitamin in a family of compounds that includes vitamins D-1, D-2, and D-3. It can affect as many as 2,000 genes in the body.

    Vitamin D has several important functions. Perhaps the most vital are regulating the absorption of calcium and phosphorous（磷）, and promoting normal immune system function. Getting enough vitamin D is important for normal growth and development of bones and teeth, as well as improving resistance against certain diseases.

    In addition to its primary benefits, research suggests that vitamin D may also play a role in: reducing your risk of multiple sclerosis（多发性硬化）, according to a 2006 study published in the Journal of the American Medical Association decreasing your chance of developing heart disease, according to 2008 findings published in Circulation helping to reduce your possibility of developing the flu, according to 2010 research published in the American Journal of Clinical Nutrition regulating mood and warding off depression losing weight or preventing heart disease.

    How do you get it? Your body produces vitamin D naturally when it is directly exposed to sunlight. A little can go a long way. All you need is 10 minutes a day of midday, pre-sunscreen sun exposure,especially if you have fair skin. Besides getting vitamin D through sunlight, you can also get it through certain foods and supplements to ensure adequate levels of the vitamin in your blood.

    As a father who works outside the home, I recognize that it is easy for me to get caught up in stress at work. Indeed, sometimes it is difficult to turn off my work focus and turn on my family focus so that I can come home and be the loving husband my wife needs and the playful father my kids want. {#blank#}1{#/blank#} Good fathers provide stability and strength to the family. As fathers, we do not let the pressures and worries of work get in the way of being there for our kids. {#blank#}2{#/blank#}

1）．{#blank#}3{#/blank#} It doesn't need to be a lot of time, but if you are able, have one­on­one time with each of your kids.

2）. Be goofy (滑稽的) with your kids. The more voices you do, the more expressive you are when you play with them, the more they will feel your love and your acceptance of them.

3）. Spend time reading to them. Allow your kids to choose a book and spend time reading some of it to them before bed. The more effort you put into it ,the more they will feel your love. {#blank#}4{#/blank#}

    As a therapist (临床医学家)  who works with children and their families, I have noticed that the better the relationship that a father has with his child, the more influence that father will have on his child. As fathers work on developing a strong link with their kids through positive interactions, they can have a positive effect on the lives of their children. {#blank#}5{#/blank#}

A．Fathers have such an important and irreplaceable role in the family.

B．Sometimes books can help you deal with children.

C．Reading stories is an excellent time for dads to practice voice imitations.

D．Here are some thoughts to help fathers keep their little ones in mind.

E．As a father he must involve hardships in all his life.

F．And the confidence can give their children a great advantage to succeed in the future.

G．Make a plan to spend time each day with your kids.

    {#blank#}1{#/blank#}Friendships between Americans can be close and real, yet disappear soon if situations change. Neither side feels hurt by this. Both may exchange Christmas greetings for a year or two, perhaps a few letters for a while — then no more.{#blank#}2{#/blank#}. This can be quite difficult for us Chinese to understand, because friendships between us develop more slowly but then may become lifelong feelings, extending (延伸) sometimes deeply into both families.

    Americans are ready to receive us foreigners at their homes, share their holidays, and their home life. They will enjoy welcoming us and be pleased if we accept their hospitality (好客) easily.

    There is another difficult point for us Chinese to understand.{#blank#}3{#/blank#} This is usually the opposite of the practice in our country where we may be generous (慷慨)with our time. Sometimes, we, as hosts, will appear at airports even in the middle of the night to meet a friend.{#blank#}4{#/blank#}. The Americans, however, express their welcome usually at homes, but truly cannot manage the time to do a great deal with a visitor outside their daily routine. They will probably expect us to get ourselves from the airport to our own hotel by bus. And they expect that we will phone them from there.{#blank#}5{#/blank#}. We will find ourselves treated hospitably(好客).

    For the Americans, it is often considered more friendly to invite a friend to their homes than to go to restaurants, except for business matters. So accept their hospitality at home!

A.Americans don't show their politeness if it requires a great deal of time.

B.Friendships between Americans usually extend deeply into their families.

C.Americans always show their warmth even if they are very busy.

D.Once we arrive at their homes, the welcome will be full, warm and real.

E.We may take days off to act as guides to our foreign friends.

F.If the same two people meet again by chance, even years later, they pick up the friendship.

G.America is a mobile society.

    Dutch officials toasted on Tuesday the opening of what is being called the world's first 3D-printed concrete bridge, which is meant to be used by cyclists. There was applause as officials wearing hard hats and workmen's jackets rode over the bridge on their bikes at the opening ceremony in the southeastern town of Gemert.

    “The bridge is not very big, but it was rolled out by a printer which makes it unique,” Theo Salet, from the Eindhoven University of Technology, told Dutch broadcaster NOS. Work on printing the bridge, which has some 800 layers, took about three months after starting in June and it is made of pre-stressed concrete, according to the university. “One of the advantages of printing a bridge is that much less concrete is needed than in the conventional technique in which a mould (泥浆) is filled,” it said on its website, adding “a printer deposits the concrete only where it is needed.”

    The eight-metre (26-foot) bridge crosses a water-filled channel to connect two roads, and it was tested for safety to bear loads of up to two metric tons in cooperation with the BAM Infra Construction company. Although designed for bikes, it could take up to 40 trucks, the designers said “We are looking to the future,” said the head of BAM, Marinus Schimmel. “3D printing meant fewer rare resources were needed and there was significantly less waste,” he added.

    The Netherlands is among countries, with the United States and China, taking a lead in the cutting-edge technology of 3D printing, using computers and robotics to construct objects and structures from scratch without using much traditional manpower. Last year a Dutch architect unveiled (提示) a unique 3D printer with which he hopes to construct an “endless loop” building. And a Dutch start-up called MX3D has begun printing a stainless-steel bridge, of which a third is already completed. The aim is to finish printing by March and lay the bridge over an Amsterdam canal in the future.

The Seven Cs of a Good Letter

    What is the secret of writing a good letter? Here are two main ones. Don't try to be fancy. Don't try to impress your reader. You will be successful if you follow these seven Cs.

    Clear. Use short, direct sentences. {#blank#}1{#/blank#}Try your tone as if the reader were right there with you. Above all, don't use an introduction.

    Correct. {#blank#}2{#/blank#}Don't guess, even for spelling. Refer to your dictionary. If you need to, check a reference book too. Use them as much as you need to.

    Complete. Don't scatter(分散) your points. {#blank#}3{#/blank#}This is good organization too.

    Courteous. Be friendly rather than overly casual. Present your information nicely even if you are complaining about something. In all letters, treat others as you want them to treat you.

    Concise. Make each point as clearly and briefly as you can.

    Conversational. This is really the secret of good writing. {#blank#}4{#/blank#}Such a letter has a natural, friendly tone. Let your personality come through naturally.

    Considerate. {#blank#}5{#/blank#}Write about what you believe the reader needs or wants to know. Try to be helpful. This will build good feeling toward you.

    The seven Cs are about writing letters. But how about school papers? Use the seven Cs. Write as if you are talking to your teacher or professor. You'll be surprised. You'll almost instantly become a good writer. And you might even enjoy writing from now on.

A. Just "talk" to the person.

B. Make them easy to understand.

C. Make sure what you say is correct.

D. Include long sentences in your letter.

E. Writing should not be taken too seriously.

F. Think of the readers' point of view as you write.

G. Finish one point completely before going on to the next.

A new study examined scientists' peer reviews, or researchers' official statements on others' work, across multiple AI-related conferences. At one such conference, those peer reviews used the word "meticulous" — a buzzword often associated with generative A.I., like ChatGPT — almost 3,400 percent more than the previous year. Other major conferences showed similar patterns. In other words, many researchers were handing, at least, parts of their peer review over to A.I.

What's going on in science is a slice of a much bigger problem. Any viral post on social media now almost certainly includes A.I.-generated elements. There are synthetic videos for children on YouTube, like music videos about parrots where the birds have eyes within eyes, singing in an unnatural voice. The narratives make no sense, and characters appear and disappear randomly.

As a neuroscientist, this worries me. Isn't it possible that human culture contains within it cognitive micronutrients — things like reasonable sentences, narrations and character continuity — that developing brains need? Einstein supposedly said: "If you want your children to be intelligent, read them fairy tales. If you want them to be very intelligent, read them more fairy tales." But what happens when a child is consuming mostly A.I.-generated waste? We find ourselves in the middle of a vast developmental experiment.

A.I.'s cultural pollution is driven by a desire to fill the Internet's appetite for content as cheaply as possible, which in turn pollutes our culture. And despite public appeals to act against it, A.I. companies are dragging their feet because it goes against the industry's bottom line to have detectable products, which they fear might weaken the model's performance, although there is no current evidence.

To deal with this general refusal to act, we need a Clean Internet Act. Perhaps the simplest solution would be to force built-in watermarking to A.I. generated outputs, like patterns not easily removable. Just as the 20th century required action to protect the shared environment, the 21st century is going to require actions to protect a different but equally critical resource: our shared human culture.