The way to King Street

Listen to the tape then answer this question.

 Why did the man need a phrasebook?

    Last week Mrs. Mills went to London（伦敦）. She does not know London very well, and she lost her way. Suddenly（突然地）, she saw a man near a bus stop. 'I can ask him the way.' she said to herself.  'Excuse me,' she said. 'Can you tell me the way to King Street, please?'
    The man smiled pleasantly（愉快地）. He did not understand English! He spoke German. He was a tourist.Then he put his hand into pocket衣袋, and took out a phrasebook（常用语手册）.
    He opened the book and found a phrase （短语）. He read the phrase slowly（缓慢地）. 'I am sorry,' he said. 'I do not speak English.'