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.

今年国家实施“全面二孩”政策，对改善人口发展战略，应对人口老龄化起到积极作用，优生优育再次成为众多家庭关注的话题．

Dear editor,

    I am not a good-looking boy and I'm not good at studying, either. Some people don't even want to talk to me. So I usually feel lonely. Sometimes I think that if I wanted to leave home, nobody would care. How can I stop feeling like this?

Peter

Dear Peter,

    Without knowing more about you, it is hard for me to give you some good advice.

    But first, I am sure that you are wrong that nobody would care if you left home. What about your parents? And other family members? It seems that you are very sad. You'd better go to see a doctor or talk to your parents. They will be able to help you.

    Secondly, I'm sure there is someone in your class who feels lonely, too. You never know how other people feel inside. Try to make friends with them.

    Or you may join a club to meet new people and to keep yourself busy.

    You need to find happiness in yourself. Write a list of all the good things about yourself, learn to like yourself, and then others will see your confidence and like you, too.

Editor

在一个密闭容器内有如下反应，反应前后测得各物质的质量如下表所示：

下列说法正确的是（　　）