【经典赏析】教材中介绍了拉瓦锡用定量的方法研究了空气的成分（实验装置如图1）。

下列说法正确的是（　　）

   Yesterday my son, daughter and I went to the grocery store. In front of us in line was a little girl with her mother. The little girl was asking her mother for a box of Smarties. The polite way she was asking almost broke the mother’s heart, “I’m sorry, Honey, but we have no money to buy it ”
   My son was watching that dialogue. By the way, he had been raking(用耙子耙)leaves our garden to raise himself some money to buy a bike. As he watched the mother and daughter leave the store, he ran to the candy counter(柜台)and bought a box of Smarties with the money .
He turned to look at me and I just nodded. He ran out after the little girl and her mother and he gave them the box. He came back and told me what he told them. “Every kid should have a pack of Smarties because they can make you smart.”
   I was so excited that I bought a pack of Smarties for my son. I told him that I was proud of him, and that was for his act of generosity(慷慨)because he gave his own Smarties to others  Quickly, he replied, “But you do nice things for people and you never get anything for it .”explained, “when you do something nice for someone, you shouldn’t expect to get anything, when you do get something you should be very thankful.”