Time spent in a bookshop can be enjoyable．If you go to a good shop，no assistant will come near to you and say．"Can I help you？"You needn't buy anything you don't want．You may just try to find out where the book you want is and read it．But if you fail，the assistant will lead you there and then he will go away．① It seems that he is not interested in selling any books at all．

There is a story which tells us about a good shop．A medical student found a very useful book in the shop．② But it was too expensive for him to buy．He couldn't get it from the school library，either．So every afternoon，he went there to read a little at a time．One day，However，he couldn't find the book from its usual place and was leaving when he saw an assistant singing to him．To his③    ，the assistant pointed to the book in the corner．"I put it there so that it couldn't be sold out．"said he assistant．Then he left and the student went on with his reading．

81．将文中①处画线句子翻译成汉语． 　　

82．将文中②处画线句子改写为同义句． 　

83．根据短文内容，在文中③处填入恰当的词． 　　．

84．Where was the book that the student was looking for？ 　　

85．What do you think of the assistant？ 　　．