Any sufficiently advanced technology,noted Arthur C.Clarke,a British science-fiction writer,is indistinguishable from magic.The fast-emerging technology of voice computing proves his（1）Using it is just like casting a spell say a few words into the air,and a nearby device can（2）your The Amazon Echo,a voice-driven cylindrical computer that sits on a table top and answers to the name Alexa,can（3）music tracks and radio stations,tell jokes,answer trivia questions and control smart（4）even before Christmas it was already resident in about 4%o of American house holds.Voice assistants are（5）in smartphones,too:Apple"s Siri（6）over 2 billion commands a week,and 20%of Google（7）on Android powered handsets in America are input by voice Dictating e-mails and text messages now works（8）enough to be useful.Why type when you can talk This is a huge shift.Simple（9）it may seem,voice has the power to transform computing,by providing a natural means of interaction.Windows,icons and menus,and then touchscreens,were welcomed as more（10）ways to deal with computers than entering complex keyboard（11）.But being able to talk to computers（12）the need for the abstraction of a user interface"at all（13）mobile phones were more than existing phones without wires,and cars were more than carri-ages without horses,so computers without screens and keyboards have the（14）to be more useful and powerful than people can imagine today Voice will not wholly（15）other forms of input and output.Sometimes it will remain more（16）to converse with a machine by typing rather than talking.But voice is destined to（17）growing share of people"s interactions with the technology around them,from washing machines that tell you how much of the cycle they have left to virtual assistants in corporate call-centres.（18）to reach its full potential,the technology requires（19）breakthroughs-and a resolution of the（20）questions it raises around the trade-off between convenience and privacy（17）选？

A. call for

B. answer for

C. account for

D. take for