You'll probably never go to Mars or sing on the stage with The Rolling Stones. But if virtual reality （VR）ever lives up to its promise, you might be able to do all these things - and many more - without even leaving your home.Unlike real reality, virtual reality means simulating（模拟）bits of our world. Apart from games and entertainment, it's long been used for training airline pilots and surgeons and for helping scientists to figure out difficult problems such as the structure of protein molecules（蛋白质分子）. Then how does it work?

Close your eyes and think of virtual reality and you probably picture something like this:a man wearing a wrap-around headset and data gloves wired into a powerful workstation or supercomputer. What distinguishes VR from an ordinary computer experiences the nature of the input and output. While an ordinary computer uses things like a keyboard, a mouse, or speech recognition for input, VR uses sensors that detect how your body is moving. A PC displays output on a screen while VR uses two screens （one for each eye） , surround-sound speakers, and maybe some forms of touch and body feedback as well.

VR has been routinely used by scientists,doctors, engineers, architects, archaeologists, and the military for about the last 30 years. Difficult and dangerous jobs are hard to train for. How  can you safely practice taking a trip to space, making a parachute jump, or carrying out brain surgery? All these things are obvious candidates for virtual reality applications.

Like any technology, virtual reality has both good and bad points. Critics always raise the risk that people may be addicted to alternative realities to the point of ignoring their real-world lives, but this criticism has been leveled at everything from radio and TV to computer games and the Internet. Like many technologies, VR takes little or nothing away from the real world: you don't have to use it if you don't want to.

   There's a good chance that something you've bought online has been in the hands of a " picker". These are the workers in warehouses (仓库) who pick, pack and ship all those things we ordered.

At Amazon and other companies, they're working side by side with robots. Experts say while the robots are replacing some human workers, the machines aren't quite ready to take over completely.

When a robot finds its storage unit,' it slides underneath, lifts it up and then delivers it to a worker they're called pickers. On a recent day, the computer told a picker to grab what looked like a fantasy board （#t 3#)game. The picker found it, packed it and placed it on the conveyer belt.

"In a traditional fulfillment center where the workers would walk to the different items, it can take hours to fulfill a customer order," Robinson says.

Now, with the help of robots, that task takes minutes and fewer humans.

So is this a sign that we're entering a new industrial revolution?

" It's definitely going to take over a lot of jobs ", says Karen Myers, a scientist at SRI, one of Silicon V alley's oldest research centers.

At the same time, she says, " We're running against the limits of technology. " Take the picker at the Amazon fulfillment center for example. Myers says those skills prove to be uniquely human.

"Our fingers are incredibly flexible and the current generation of robotic operators are getting much, much better," she says. "But they're just not quite there yet."

There's also the robot's brain.

Remember that board game the Amazon worker was looking for? She could barely see the box when it was filled into the storage bin——but she could tell it was a board game. Robots can't do that.

Technologists say that, increasingly, humans will work side by side with robots——instead of robots working alone.

Amazon says robots and humans enabled the Tracy warehouse to fulfill customer orders faster. That means more customers and more human workers.

   Scientists are debating how to limit their newly-discovered power to change genetic structure. Scientists have already changed the genes of farm animals and agricultural plants to make them more productive or stronger. But now they can also change genes in wild animals and plants. These genes would continue into later generations. For example，it may be possible for scientists' to remove from existence the kind of mosquitoes that carry the Zika virus. They might also be able to permanently remove species of plants and animals that are destructive to other species.

In a report published last week，the U.S. National Academies of Sciences，Engineering and Medicine said it supports continuing research on this kind of gene control. But it warned that it is not possible to know what will happen when these changed plants and animals are released into the wild.

Sixteen biologists，ethicists（伦理学家）and policymakers are on a National Academy of Sciences（NAS）committee that is examining the issue. They say that there is value to the new technology. But，they say，there is not enough evidence to support the release of changed organisms（生物）from the laboratory into nature.

Many people would support stopping mosquitoes and rats from carrying diseases. But scientists say we must understand the possible scientific，ethical，legal and social results of such action before we decide whether to take it. Gene modification is spread through reproduction（繁殖）.Changed genes will continue to spread as long as an animal or plant continues to reproduce. They cannot be limited to a farm or kept within a country's borders. Scientists are wondering what may happen if a changed organism mates with another species. They are not yet sure how the changed genes would affect the other species. It is possible that those genes could harm those creatures or even lead to their disappearance from our planet.

I'm Li Hua. Recently we had a discussion _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

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Li Hua

   New technology rules the whole world now. But I still remember when I was a child, I did not have a cell phone or a computer because it was not necessary at all in those days. The Internet was not popular and the touch screen technology was unknown.

At this time here in the US smartphones are really a need, especially for young and business people. There are many applications (应用软件) really useful like maps, dictionaries, e-mails and games.

For me, I use my smartphone to check the weather and to look for something on the Internet and of course to keep communicating through calls and texts. Besides, I like music applications, GPS and Facebook.

Many tests have discovered that cell phones cause damage to us because they send out radioactive (具有放射性的) waves to our bodies and this could cause cancer.

Psychologists say that these devices can affect behavior and I believe everyone knows it is harmful to the eyes if we are sitting for a long time in front of the computer. However, it seems to be difficult for us to give up, even if we know how bad it is for our health. The use of technology becomes more and more important in our lives.

I think the use of technology has brought us unimaginable things. If we use technology correctly, I am sure it would be possible to decrease the damage to our bodies.

Keep in mind that it is important not to focus only on technology, but to spend time with our families and people close to us.