美国独立后成功地进行了制度创新，其宪法在中央政府的权力构建中体现了三权分立的原则。阅读下列材料，回答问题。

材料一 众议院……有弹劾(违法失职的总统、副总统和高级文官)的全权。……参议院有审讯一切弹劾案的全权。……凡必须经参议院及众议院一致同意的命令、决议……应经总统批准……经参议院的协议及同意，并得该院出席议员三分之二赞成时，总统有权缔结条约；总统提出大使、公使、领事、最高法院法官及合众国政府其他官吏，经参议院的协议及同意时，任命之……——摘自《美利坚合众国宪法》

材料二 美国总统威尔逊本是国联的发起人和积极的鼓吹者，但是……参议院拒不批准《凡尔赛和约》。结果，美国没有加入国联……

材料三 国会授权罗斯福进行大规模的干预和调节……但在罗斯福新政的前期，最高法院与行政间则展开激烈争吵。法官们……先后宣布新政的几个主要法令违宪，予以废止。——据吴于廑、齐世荣主编《世界史》等改编

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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.