中央电视台有这样一则廉政广告:面对红包,老师对家长说:“您在伤害我!”医生对患者家属说:“您在侮辱我!”国家公务员对审批者说:“您在藐视我!”交警对才考驾驶证的人说:“请您尊重我!”这则广告启示我们(　　)

①尊重他人,要尊重他人的劳动

②自尊的人自爱

③自尊的人不会做有损自己名誉、人格的事

④收红包被人知道后,有损自己的尊严

已知AC⊥BC于C，BC=a，CA=b，AB=c，下列图形中⊙O与△ABC的某两条边或三边所在的直线相切，则⊙O的半径为$\frac{ab}{a+b}$的是（　　）

    Cindy, Jerry and Mary are giving their ideas about what a good friend should be like.

    Cindy: I think a good friend should be honest(诚实).That's the most important thing and is where a real friendship(友谊) starts. If a friend isn't honest, he may lost his friends' trust.

    Jerry: I think a good friend should be generous. Here “generous” doesn't mean he has to give his friends his money or his clothes. It means he should share his ideas and feelings with his friends. So, his friends can know him better in this way.

    Mary: For me, a good friend should understand his friends. When there's something bad between him and his friends, he must put himself in his friends' place and think more for his friends.