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?

    There exist cruel wars, fighting and sadness in the world today, so it's not only necessary, but also essential to have a good sense of humor just to help us go through difficult times in out lives. Putting a smile on someone's face when you know they are feeling depressed, as the saying goes, makes me feel good and warms my heart.

    How would you feel if you could not joke around with wife, husband, child, co-worker, neighbor, close friend, or even just someone that you are standing in line with at your corner store? I am always saying things that make others smile or laugh, even if I don't know the person I'm joking around with. My Grandma always found humor in everything she did, even if it was the hardest job anyone could imagine. This not only relieves stress in any situation, but also is a common manner to speak to others that are around you.

    I know of a few people that don't have a funny bone in their bodies, as they say. Everyone around them could be rolling on the floor after hearing a great joke and they would sit there without the slightest smile on their faces. They don't get the joke that makes others laugh. I am, busting a gut while they just sit there, looking at me as if I were from outer space. How can people not get a really funny joke?

    Laughing is essential to keep your stress levels under control. Without humor, we would find ourselves with a lot of psychological problems, or on a lot of medications to keep us from going crazy. There is too much sadness and bring a little light into our lives.

    Therefore, I believe our best medicine is to get together and tell some jokes and have some fun laughing together.

    The following are the top things to do in Tampa Bay on the weekend.

    Chinese scientists recently have produced two monkeys with the same gene, Zhong Zhong and Hua Hua, using the same technique that gave us Dolly the sheep. These monkeys are not actually the first primates(灵长类)to be cloned. Another one named Tetra was produced in the late 1990s by embryo(胚胎)splitting, the division of an early-stage embryo into two or four separate cells to make clones. By contrast, they were each made by replacing an egg cell nucleus(卵原子核)with DNA from a differentiated body cell. This Dolly method, known as somatic(躯体的) cell nuclear transfer(SCNT), can create more clones and allows researchers greater control over the edits they make to the DNA.

    Success came from adopting several new techniques. These included a new type of microscopy(显微术) to better view the cells during handling or using several materials that encourage cell reprogramming, which hadn't been tried before on primates. Still, the research process proved difficult, and many attempts by the team failed. Just two healthy baby monkeys born from more than 60 tested mothers. This leads to many researchers' pouring water on the idea that the team's results bring scientists closer to cloning humans. They thought this work is not a stepping stone to establishing methods for obtaining live born human clones. Instead, this clearly remains a very foolish thing to attempt, and it would be far too inefficient, far too unsafe, and it is also pointless.

    But the scientists involved emphasize that this is not their goal. There is now no barrier for cloning primate species, thus cloning humans is closer to reality. However, their research purpose is entirely for producing non-human primate models for human diseases; they absolutely have no intention, and society will not permit this work to be extended to humans. Despite limitations, they treat this breakthrough as a novel model system for scientists studying human biology and disease.

    My name is Kobus Vermeulen. On February 16, 2015, I was one of five South Africans among the 100 people selected by Mars One to begin training to live on the Red Planet. The Dutch not-for-profit's aim is simple: build a human colony (殖民地) on Mars. Since I have begun this journey, the one question that people ask me most is why I want to leave a good planet for wasteland. Here is why.

    I have been interested in Mars since I was a child, and I always thought that if I had the opportunity to leave the planet, I would take it. So the why begins with a child's dream.

    However, as I grew, so did the why. In my eyes, since the 1970s the public has stopped trying to learn more about space. We've put our dream aside. We're satisfied with getting our dose (一份) of the future from sci-fi movies and comic books. And so the first part of my motivation (动机) is to get people thinking about space travel and the colonization (殖民化) of other planets in real terms again instead of just as sci-fi visions of the future.

    If we want that future, the truth is that we have to build it, and anything worth doing comes with risks. Somebody has to take the risks, and I, along with thousands of other people, am willing to take them.

    But it goes deeper than that. If the task of Mars One is even partially (部分地) successful, it will encourage a new generation of scientists and engineers that will build us an even better future.

    Without a dream, there is no reason to build those things. The public that does not try to understand science and technology does not choose good leaders. Leaders who don't care for science and technology do not make budgets (预算) for it. Besides, without the money, the dream dies. Projects like Mars One are like a focusing lens (聚焦透镜) for dreams. It is an opportunity to change hearts and minds at the grassroots level.

    AI(人工智能)makes our lives easier and better. Let's see the amazing AI.