上官吉庆说，厕所文明，是衡量一个国家、一座城市文明程度的重要标志。所以，厕所虽小，却关乎大民生。关乎大文明。开展“厕所革命”，让城市更文明，让生活更关好，是民众的愿景，更是我们的责任。让我们行动起来，从我做起、从小事做起，积极支持并参与“厕所革命”，促进“厕所革命”早结硕果、广惠于民。

科学知识广泛应用于生产和生活，请你利用所学的科学知识回答下列问題，

    Today is Tom's birthday. After school he walks past the shop on the street corner. He looks into the window. That pair of trainers(运动鞋) is still there. He really wants to have them.

    He is very sad and walks away. He knows his mother can't buy him anything, because his mother has no money. The trainers are too expensive. He doesn't go home at once , because his mother can notice（注意）his worry. So he goes to the park and sits on the grass. Then he sees a boy in a wheelchair(轮椅). He finds that the boy moves(移动) the wheels with his hands. Tom looks at him carefully. The boy has no feet. He looks at his own feet. "It's much better（更好）to be without shoes than (比) without feet." he thinks. There is no reason for him to feel so sorry and sad. He smiles and thinks he is happy.

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