学校里正在上自然科学课。老师提问:“现在谁能跟我说一说对热的认识?”一个男孩举手回答:“老师,热能使东西膨胀,冷能使东西缩小。”老师说:“很好,举一个例子。”“夏季,白天变长,因为天气太热;冬季,白天缩短,因为天气太冷。” Natural science class is taking place in school. Teacher asked: “Now who can tell me about the understanding of heat?” A boy raised his hand to answer: “Teacher, the heat can make things expand, cold can make things shrink. ” The teacher said: “Very good Give an example. ”“ In summer, the daytime becomes longer because the weather is too hot; in winter, the daytime is shortened because the weather is too cold. ”