Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word  or phrase that best fits each of the numbered blanks. Fill in the appropriate word in question 39

      It is relatively easy for computers to speak. A computer that says ‘please’ and ‘thank you’  in the right    places is (35) ___   miracle of science ,but recognizing the words that make up normal , continuous human speech is another (36) ___ 

     Not until now have computer been programmed to (37) ___ to a range of spoken commands.Until recently it was thought that computers would have tobe programmed to the accent and speech hahits of each user,and only then would be able to respond(38) ___to their master’s or mistress’s voice.Now rapid progress is being made (39) ______systems programmed to adapt easily to each new speaker.

     The IBM Tangora system,under development at the end of 1980s was claimed to (40) ______a spoken vocabulary of 20,000 words with 95 percent accuracy. The system includes a processor that can  make informed guesses as to(41)______is a likely sentence.That system has been programmed not only with grammatical rules,but also with an analyssis of a vast quantity of office correspondence.On the(42) ______

 of this information ,the machine can calculate the probability of one particular word following another.

      Statistical probability is necessary for computers to interpret not only speech but also

(43) ______data.

Security systems can distinguish between faces they have been taught to recognize,but never has a computer

been able to match a human’s ability to make sense of a three-dimemsional scene

(44) ______identifying all objects in it.

                  (From ‘Heinle & Heinle TOEFL Test Assistant .Grammar’ by Milada Broukal)