4．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 （噴） 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（樹脂） 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，10years 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 （笛子），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？
9．According to the article，in the future，the 3D printing technology willB．
A．enable people to make better purchases online
B．change the way we make many products
C．be applied as widely in our daily life as computers
D．shorten the time it takes for people to get what they buy online
10．What happened in the 3D printing industry last year？D
A．The 3D printing technology was taken out of the factory．
B．The 3D printing technology began to be used in various fields．
C．The 3D printer was used for medical treatment for the first time．
D．The 3D printer became more affordable for consumers．
11．How is the last paragraph developed？A
A．By giving examples．
B．By making comparisons．
C．By analyzing the cause and effect．
D．By presenting research findings．
12．What is the best title of the passage？D
A．Great Demand for 3D Printers
B．Technology in the Future
C．Online Shopping Disappearing
D．Printing out Everything．
