Once upon a time a man became a great archer(射手).He asked the king to declare him as the greatest archer of the country. The king was about to do so when an old servant of the king said，“Wait，sir.I know an old man who lives in the forest. He is a much greater archer. Let this young man go to him and learn from him for at least three years.”
   The man could not believe that there could be a greater archer than him，but he went and found the old man and he was! For three years he learned from him.Then one day，when he thought he had learned everything，the thought arose in him：“If I kill this old man，then I will be the greatest archer.”
   The old man had gone to cut wood and he was coming back carrying wood on his shoulder. The young man hid behind a tree,waiting to kill him. He shot an arrow(箭). The old man took a small piece of wood and threw it.It struck the arrow and the arrow turned back and wounded the young man.The old man came，took out the arrow and said.“I knew that some day or other you were going to do this. That's why I have not taught you this secret. There is no need to kill me. My master is still alive,and I'm nothing before him. You must be with him for at least thirty years. And he is very old，So go fast! Find the old man!”

①朋友带给我们温暖、支持和力量，让我们感受到生活的美好

②在人生旅途上，朋友伴我们同行

③朋友丰富我们的生活经验，友谊让我们更深刻的体悟生命的美好

④朋友会为我们提供一切需要，满足我们所有的要求

斜面长10米，高2米，机械效率80%，将一重为400牛的物体沿斜面底端匀速拉到顶端，则物体与斜面之间的摩擦力为（　　）

①人与人之间没有高低贵贱之分

②人与人之间的平等体现为人格和各项基本权利的平等

③每个人都应当享有被尊重的权利

④每个人获得人格尊严需要法律的保障和自觉行动