SEE a cell phone 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 3-D 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 3-D printer uses are mainly plastic, resin  and certain metals. The thinner each layer is --- from a millimeter 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 3-D 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 3-D printing industry--- printers became much cheaper. For example, 10 years ago a desktop 3-D printer might have cost PS20,000 (200,000 yuan), while now they cost only about PS 1,000, according to the BBC. Taken out of the factory and introduced to more diverse and common uses, 3-D 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 3-D printer, according to Science Daily. The fake ear looks and acts exactly like a natural one. However, as 3-D printing becomes more commonplace, 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   on your personal 3-D printer, who will visit a retail   store again?" an expert in 3-D printing told Forbes News. Even more frightening, what if anyone in the world could use a 3-D printer to print out a fully functioning gun? According to the article, in the future, the 3-D printing technology will   _  .
enable people to make better purchases online be applied as widely in our daily lives as computers change the way we make many products shorten the time it takes for people to get what they buy online