七年级数学上册第2章有理数及其运算4有理数的加法第2课时ppt课件新版北师大版.ppt

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1、第二章有理数及其运算第二章有理数及其运算 4有理数的加法有理数的加法 第第2课时课时 2018年秋年秋数学七年级上册数学七年级上册 B和和 ba 先把后两个数相加先把后两个数相加 a(bc)C C B 25.5 14(14)0 3000 1 D B D 0 10 全文结束！再见全文结束！再见o study whether experiences during teen years would influence adult health.So they followed 171 teens,starting when the kids were just 13.They interviewed

2、 each one every year for five years，and also spoke to these teens closest friends，who provided additional information about the quality of their friendships.The same 171 people were interviewed again at ages 25,26 and 27.This time,the questions surveyed each persons overall health.When the researche

3、rs analyzed the data,they found a strong connection between a teens behavior and adult health.Teens who had close friends grew up to be the healthier adults.Whether teens held back their feelings or expressed them to close friends also influenced later health.Those who held back their feelings were

4、more likely to be sick as adults.The connection held up even after the scientists accounted for other possible influences on health.Weight，family income and drug use were all examined.So were mental health issues，such as anxiety and depression.And in these people，such other factors did not explain a

5、dult health as well as teen friendships did.Getting along with the crowd may have benefits,says Allen,but there are also drawbacks.Teens who are more independent tend to do better at school and work.And peer pressure may lead some kids to engage in risky behavior,such as smoking,drinking or using drugs.Dealing with it is an ongoing challenge，Allen acknowledges.“Finding the right balance is the key.Teens shouldnt lose heart for not finding this easy.”And,he adds，“Parents need to be understanding about the pressures teens face.”