题目

小明家离学校2km，他平时步行上学，需要半小时才能到达学校。最近，他使用共享单车上学，若骑行共享单车速度约为5m/s，求：（1）小明步行上学的平均速度是多少米/秒？（保留1位小数）（2）小明骑行共享单车上学节约的时间。 答案：【答案】（1）1.1m/s（2）1400s【解析】（1）由题知，s＝2km＝2000m，t1＝0.5h＝1800s，小明步行上学的平均速度： ；（2）由 可得使用共享单车上学的时间： ，可以节约时间：△t＝t1﹣t2＝1800s﹣400s＝1400s. When Justin Tong was a child, other kids felt sorry for him. His parents always made him do lots of housework such as taking out the rubbish and sending newspapers. But when he grew up, he was better than his childhood friends and lived a happier and healthier life.This is the finding of a 40—year study in London. It showed that the children who worked hard in childhood had a richer and a happier future. "Children who worked in the home or community（社区）got more abilities and felt they were good people.” said Daniel Brown, the leader of the study. "Because they felt good about themselves, and others felt good about them.”Brown's study followed 456 children. It compared the children's mental health（心理健康）with their childhood activity. The children who do part—time jobs, housework or work hard in school are much better at dealing with problems when they grow up.Working at any age is important. Childhood activities help a child have the sense of responsibility（责任）, independence, confidence（自信）and competence （竞争）. They also help him understand that people must learn to work with others. The most successful people are those who know how to do this.However, work isn't everything. As Tolstoy once said, “One can live wonderfully in this world if one knows how to work and how to love, to work for the person one loves and to love one's work.”【1】How was Justin's childhood?A.Relaxing.B.Interesting.C.Busy.【2】According to the passage, the study in London ________.A.lasted 40 daysB.followed 456 childrenC.was done by Tolstoy【3】The study shows____________.A.childhood activities have nothing to do with the children's futureB.the most successful people have a happy childhoodC.people who do more childhood activities have a better future【4】What is the meaning of the underlined word "independence"?A.负担B.骄傲C.独立【5】What's the purpose of the passage?A.To talk about an interesting study.B.To tell us about childhood activities.C.To encourage children to work hard.