Time spent in a bookshop can be most enjoyable, whether you are book-lover or only there to buy a book as a present. You may even have entered the shop just to find a shelter from a sudden shower. Whatever the reason is, you can soon be totally unaware of your surroundings. You soon become attracted in some books or others, and usually it is only much later that you realize you have spent too much time there and must dash off to keep some forgotten appointments. This opportunity to escape the realities of everyday life is the main attraction of a bookshop. A music shop is very much like a bookshop. You can wander round such a place to your heart's content. If it is a good shop, no assistant will approach you with the greeting "Can I help you?" You needn't buy anything you don't want. In a bookshop an assistant should remain in the back ground until you have finished reading. Then, and only then, are his services necessary. Once a medical student had to read a text book which was far too expensive for him to buy. He couldn't obtain it from the library and the only copy he could find was in a certain bookshop. Every afternoon, therefore, he would go along to the shop and read a little of the book at a time. One day, however, he was disappointed to find the book missing from its usual place. He was about to leave, when he noticed the owner of the shop beckoning to him. Expecting to be told off, he went towards him. To his surprise, the owner pointed to the book which was tucked away in a corner. "I put it there in case anyone was tempted to buy it!" he said, and left the delighted student to continue his reading. According to the passage, the main attraction of a bookshop is   _   .
the chance to get free from the reality learning something from the books a shelter from a sudden shower the surrounding of books