【经济交流】

材料一：丝绸之路路线图

材料二；郑和七次下西洋，海上丝绸之路盛极一时．他每到一地，都以中国的丝绸和瓷器换取当地的特产或馈赠当地的国王，与当地居民公平交易，互通有无，不占别国一寸土地，未掠夺他人一分财富．   ﹣《郑和下西洋﹣伟大的和平使者》

材料三：15世纪，追求财富的欧洲人梦想去东方发财，开始探寻通往东方的航路．

【文化交流】

材料四：

【政治交往】

材料五：1955年众多亚非独立国家的首脑，聚集在印度尼西亚的万隆，举行第一次没有殖民主义国家参加的亚非国际会议．    ﹣人教版八年级下册

材料六：中华人民共和国成立后，美国对新中国采取政治上孤立、经济上封锁、军事上包围的政策，中美关系长期以来处于敌对状态．二十世纪七十年代，随着国际形势的变化，中美两国领导人都认为有必要改善两国关系，实现双边关系正常化．     ﹣中华书局《中国历史》（八年级下）   

下列相关叙述正确的有
①一对夫妇生了四个孩子，其中只有一个孩子患有白化病，则该夫妇一定均为杂合子。
②表现型相同的个体，基因型不一定相同。
③1个具有2对同源染色体的精原细胞通过减数分裂最终形成4种精子（不考虑交叉互换）。
④隐性基因是指在生物体不能表现的基因。

阅读理解

    I was sure that I was to be killed. I became terribly nervous. I searched in my pockets to see if there were any cigarettes, which had escaped their search. I found one and because of my shaking hands, I could barely get it to my lips. But I had no matches, they had taken those. I looked through the bars at my jailer. He did not make eye contact with me. I called out to him “Have you got a light?” He looked at me, shrugged and came over to light my cigarette. As he came close and lit the match, his eyes inadvertently（不经意地）locked with mine. At that moment, I smiled. I don't know why I did that. Perhaps it was nervousness, perhaps it was because, when you get very close, one to another, it is very hard not to smile. In any case, I smiled. In that instant, it was as though a spark jumped across the gap between our two hearts, our two human souls. I know he didn't want to, but my smile leaped through the bars and generated a smile on his lips, too. He lit my cigarette but stayed near, looking at me directly in the eyes and continuing to smile.

    "I kept smiling at him, now aware of him as a person and not just a jailer. And his looking at me seemed to have a new dimension too. “Do you have kids?” he asked. “Yes, here, here.” I took out my wallet and nervously fumbled for the pictures of my family. He, too, took out the pictures of his family and began to talk about his plans and hopes for them. My eyes filled with tears. I said that I feared that I'd never see my family again, never have the chance to see them grow up. Tears came to his eyes, too. "Suddenly, without another word, he unlocked my cell and silently led me out. Out of the jail, quietly and by back routes, out of the town. There, at the edge of town, he released me. And without another word, he turned back toward the town.

    “My life was saved by a smile.” Yes, the smile― the unaffected, unplanned, natural connection between people. I really believe that if that part of you and that part of me could recognize each other, we wouldn't be enemies. We couldn't have hate or envy or fear!

 探究杠杆的平衡条件．