20. A. do with    B. deal with    C. make       D. settle

3

Workers aren't allowed to go into a huge underground computer center  1  they step up to a machine that  2  a quick picture of the tiny blood vessels(管) inside their eyes.

   If the machine can't  3  the picture with images in its computer, the worker is 4  by security (安全) guards.

   Each person has his own pattern of blood vessels in his or her eyes. And unlike a key, the pattern can't be  5   .

   Old --fashioned keys and locks may soon be things of the past.

   High--tech security devices(装置) are being  6  at military bases, computer centers, nuclear plants and banks. Companies that  7   the machines say they'll someday be used in people's homes and cars.

   Already, a Japanese firm has fixed devices that  8  people's fingerprints in 360 new homes. The machines open the doors only for the  9  of the houses.

   The new security devices are selling well because thieves and spies are getting better at breaking  10  buildings and computers that are protected by  11. Since  12  can steal or copy a fingerprint or eye pattern, the new machines are  13 .

     14  new machines recognize voice patterns. Two American companies use voice--recognition machines to keep an eye on their computers.

   Inexpensive voice--recognition machines may someday  15  locks on cars. The doors would open only for the owners. The devices would  16  the owners  17 $ 270.

    Although the up--to--date devices are  18  , scientists must still solve a(n)  19  problem. How wi11 a boy borrow his dad's car without borrowing dad's  20  ?

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