阅读下列短文，并做每篇短文后的题目。从每小题所给的四个选项中，选出能回答所提问题或完成所给句子的最佳答案。

　　Passing through the Atlanta airport one morning, I caught one of those trains that take travelers to their boarding gates．The free trains run back and forth(来回)all day long．Not many people consider them fun, but I heard laughter(笑声)．At the front of the first car were a man and his son who was about five years old．

　　“Here we go! Hold on to me tight(紧紧地)! ” the father said．“Look out there! See that pilot? I bet(打赌)his walking to his plane．” The son stretched(伸出)his neck to look．

　　As I got off, I remembered something I'd wanted to buy．I was early for my flight, so I decided to go back．I did and just as I was about to go back to the train for my gate, I saw that the man and his son had returned, too．

　　“I want to ride some more! ”

　　“More? ” the father asked, “You’re not tired?”

　　“It is fun! ” his son answered．

　　“All right, ” the father replied, and when a door opened we all got on．I realized that the father and his son were just riding this shuttle together, making it exciting, sharing each other's company(陪伴)．

　　There are parents who can afford to send their children to Europe or Disneyland, but the children turn out rotten(被宠坏)．There are parents who live in million-dollar houses and give their children cars and swimming pools, but something goes wrong．Why?

　　The answer is so simple：parents who care enough to spend time, to pay attention and to try their best．It doesn't cost a cent(美分), but it is the most valuable thing in the world．

(1)

(2)

(3)

(4)

(5)