techniques , but he admitted there would be difficulties in meeting his goal . “ For example , if you run out of ink while printing on paper , you will throw that paper away . But you cannot throw half-completed buildings away if your material gets stuck , ” he said . Although the printed house is not available to visit , there is a chance for people in Shanghai to see items printed in 3D. The Belgium-based company Materialise NV held a 3D printing exhibition in Shanghai that started in late 2012 and ended in the middle of 2013 . The company is eager to show Asia what is possible with 3D printing . “ All the pieces shown here are what cannot be made through traditional techniques . A good example of this customization is hearing aids . More than 10 million people already use 3D printed hearing aids, all made according to the size of their ears , ” said Wim Michiels , executive vice-president at Materialise NV . “ You can produce anything whenever and wherever you like . You don’t need to set up production lines for pieces that only need a limited amount of products . Setting up a production line is a lot of work . It takes a long time and is very expensive for a limited number of pieces , ” said Michiels . Kim Francois , managing director of Materialise China , said their European and American clients have already taken the next step toward additive manufacturing with small series production such as hearing aids . 小题1:What is mainly talked about in the text ? A. The development of 3D printing . B. A 3D printing show in Shanghai . C. Varieties of items printed in 3D . D. The company Materialise NV . 小题2:According to Behrokh Khoshnevis , what is the main difficulty in printing buildings ? A．Time . B．Technique . C．Space . D．Material . 小题3:The example of 3D printed hearing aids was mentioned to show that ______________ . A．these items used to be impossible to make B．3D printing has a large market share C．3D hearing aids help people hear better D．people need different sized hearing aids 小题4:According to the text , 3D printing is suitable for ___________ . A．mass production B．making small items C．small series production D．reducing production costs