The old way of making things involved taking lots of parts and screwing or welding them together. Now a product can be designed on a computer and “printed” on a 3D printer, which creates a solid object by building up _____19 __________ layers of material. The digital design can be tweaked with a few mouse clicks. The 3D printer can run unattended, and can make many things which are too complex for a traditional factory to handle. In time, these amazing machines may be able to make almost anything, anywhere—from your garage to an African village.
The applications of 3D printing are especially _____20_____ mind-boggling. Already, hearing aids and high-tech parts of military jets are being printed in customized shapes. The geography of supply chains will change. An engineer working in the middle of a desert who finds he lacks a certain tool no longer has to have it delivered from the nearest city. He can simply download the design and print it. The days when projects ground to a halt for want of a piece of kit, or when customers complained that they could no longer find spare parts for things they had bought, will one day seem quaint.
【題組】21. Which of the following statements is true?
(A) 3D printing technology is highly sophisticated. Currently there is no factory that is superior to it.
(B) In the future, there will no longer be demand for spare parts.
(C) 3D printing is largely used in areas where mass production is needed.
(D) Industrial zones will no longer have the same degree of privilege they currently enjoy.