根据短文理解，选择正确答案。

    A young woman was walking through a supermarket to pick up a few things when she noticed an old man following her around．Thinking nothing of it，she ignored him and went on shopping．After she got what she wanted，she went to checkout line，but the old man got in front of her．

    “Pardon me!” he said，“I'm sorry if my staring（盯）at you has made you feel uncomfortable（不舒服的)，it's just because you look like my granddaughter，who just died recently．And I miss her very much．”

    “I'm very sorry，”said the young woman．“Is there anything I can do for you?”

    “Yes．” the old man said．“As I'm leaving，can you say ‘Good-bye，grandpa' to me? It would make me feel so much better．”

    “Sure，”answered the young woman．

    As the old man was leaving，she called out．“Bye-bye，grandpa!”

    When she stepped(迈步) up to the checkout counter（收银台），she saw that her total was $178.50．

    “How can that be?” she asked．“I only bought a few things!”

    “Your grandpa said you would pay for him，” said the clerk.

读下列材料，完成下列问题。

材料一：城市的“空心”现象

20世纪70年代以来，一些国家的大城市中心区人口开始向郊区移动，在城市周围形成新城或卫星城，并将城市文化和产业等带到郊区，在郊区构建了许多超级市场、高级住宅、大型停车场，且在老城区和新城区或卫星城之间迅速发展高速公路和地铁等交通运输，整个都市区人口出现负增长。

材料二：“部分国家城市化及其经济发展情况统计图”(左图)和“部分国家城镇人口在总人口中所占百分比统计图”(右图)。