Printing images is easy. Just select an image of a purple robot on your PC, for example, and press print. Your home printer exactly shoots drops of ink onto a flat piece of paper, creating the robot’s 2-D image. “Printing” 3-D objects is different. Take the purple robot. First select a file of the 3-D printer. Immediately, the printer begins making noise, and a nozzle (喷嘴) releases plastic material in thin layers. In two or three hours, a 3-D purple robot is standing before you.

3-D printing has developed to the point where printers can now create high-quality objects using a variety of materials, including metals. That means 3-D printers can now make final products that meet high industrial standards. 3-D printers are already being used to make parts for racecars and jets as well as man-made limbs and hearing aids.

So far, few homes have 3-D printers. That’s because 3-D printing is not only new to most people but also quite expensive. To bring 3-D printing to the masses, some retail stores (零售商店) plan to offer the service. For example, the Staples chain of office supply stores has announced that it will offer 3-D printing in Europe beginning in 2013. Customers will be able to submit their own 3-D designs to Staples website for printing. After the job is done, they’ll pick up their item at a nearby Staples store or have it mailed to their homes. This service is sure to encourage many more people to try out 3-D printing.

1.According to this article, who are 3-D printed parts already helping?

A. People with physical disabilities.

B. People in the solar energy field

C. People who lack suitable housing

D. People in need of computer skills

2.What will customers need in order to submit their designs to Staples?

A. A credit card account

B. Its local phone number

C. Professional experience

D. Access to the Internet

3.What does the writer of this article imply about 3-D printing?

A. Its inventor is famous

B. Its future looks bright.

C. It is still quite cheap.

D. It will be of little use.

4.What do we learn about the 3-D purple robot?

A. How long it can usually last

B. How it can darken its own color

C. How it gradually takes shape

D. How much it costs to produce

My son ,Izzy, was a nine-year-old boy and had been begging me to please let him find his way home by subway, by himself. After all, we live in New York City, and getting around by public transportation is a basic part of life. It is also the first step toward feeling grown-up. So on that sunny Sunday,I gave him a subway map, a transportation card,$20 for emergencies, and a couple of coins so that he could call me if necessary. I didn’t give him a cell phone because nine-year-olds lose things. A few days later, I wrote about his adventure,or non-adventure for a newspaper. Little did I realize the idea that a kid could tour the city on his own, and that a mom would let him, was big news.

It turned out that many TV shows called me and asked for an interview. Bloggers were going crazy, so I started a blog, too, and letters came pouring in. Finally I found out why this was such a big story: we have become fearful for our children. Fear is hardly a new thing for parents, of course. But the fear of letting our children out of sight for even a second-that’s new. How did this happen? How did it become too scary to let kids be kids? I asked the question when the reporter Trevor Butterworth interviewed me.

“News reports,” he answered. “News reports scare the pants off you. What is scarier than a kidnapped(绑架) kid no matter how far away?Because there are so many such stories, it starts to feel as if kidnappings are happening all the time. That’s why the kid-on-the-subway story surprises the whole world.”

Izzy probably did a good job. He simply proved that kids could leave home alone and return home safely! But he didn’t think it was a big deal. “It was fun,” he said. “But I missed some classes because of the interviews.” Sometimes it really pays to be brave.

1.Why did the author let her son take the subway alone?

A. Because she always let her son do whatever he wanted.

B. Because she believed that her son had memorized the subway map.

C. Because she thought it would be big news around the whole world.

D. Because she felt traveling by subway in New York was a basic life skill.

2.The author gave her son all the following when he traveled alone EXCEPT_______.

A. a map. B. a cell phone.

C. a transportation card D. some money.

3.The author didn’t expect that after she wrote her son’s story for a newspaper, __________.

A. a blog would be started in her name

B. her son would receive so many letters

C. many TV shows would want to interview her

D. many TV stations would want to film her son’s story

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