单选题 The human face is a remarkable piece of work.The astonishing variety of facial features helps people 26_____ each other and is crucial to the formation of complex societies.So is the face's ability to send emotional signals，whether through an 27_____ blush or the artifice（欺骗）of a false smile.People spend much of their waking lives，in the office and the courtroom as well as the bar and the bedroom,28_____ faces，for signs of attraction，hostility，trust and deceit.They also spend plenty of time trying to dissimulate（掩饰）.

Technology is rapidly catching up with the human ability to read faces.In America facial recognition is used by churches to 29_____ worshippers' attendance; in Britain，by retailers to spot 30_____ shoplifters.This year Welsh police used it to arrest a suspect outside a football game.In China it 31_____ me identities of ride-hailing drivers，permits tourists to enter 32_____ and lets people pay for things with a smile.Apple's new iPhone is expected to use it to unlock the homescreen.

Set against human skills，such applications might seem incemental,（增加的）.Some breakthroughs，such as flight or the Internet，obviously transform human abilities; facial recognition seems 33_____ to encode them. Although faces are peculiar to 34_____ ，they are also public，so technology does not，at first sight，intrude on something that is private.And yet the ability to record，store and analyse images of faces cheaply，quickly and on a vast scale promises one day to bring about 35_____ changes to notions of privacy，fairness and trust.

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