2000年前，丝绸是中国的名片；1000年前，瓷器是中国的名片；500年前，茶叶是中国的名片……，其中与“丝绸是中国的名片”有关的历史事件是(     )

阅读材料，探究问题。

      美国时代看来一帆风顺。美国经济规模是日本的两倍还要多，美国军备开支超过了世界其他大国总和。中国习惯性地被视为美国的未来挑战者，但中国进入世界前列尚需数十年时间。恐怖分子对纽约与华盛顿的袭击肯定挫伤了冷战结束与西方胜利所带来的安全感，但它们并不会危及美国的霸主地位。的确，袭击事件已重新激起了美国参与全球性事务的欲望。至少在可预见的将来，美国继续占据至高无上的地位，它在对中国保持警觉的同时将继续打击伊斯兰恐怖主义。

      上述观点代表了目前的流行看法，可是这种看法与现实差距太大。不但美国的统治地位不如其外表那样稳固，而且这种地位已开始被削弱了。崛起的挑战者不是中国或伊斯兰世界，而是欧洲联盟。这个政治实体正处于集中整合欧洲各个不同民族国家的资源以及历史抱负过程之中。

      ……

      历史正在轮回。在摆脱了大英帝国之后，美国成为一个联邦，成为一个世界主要国家，最后它使得欧洲列强黯然失色。现在轮到欧洲上台并摆脱拒绝交出其至高无上特权的美国的时候了。——（美）查尔斯▪A ▪库普钱《谁是美国终结者？》

胚芽鞘产生生长素的部位、感受单侧光刺激的部位和弯曲生长的部位分别是         

    One day an American called Simon went to London to visit his friend, Rick. Rick told him that his flat was on the first floor. When he arrived, Simon went straight to the first floor of the building. But he was told that there was no Rick on that floor. Do you know why?

    In fact, the British call the first floor of a building the ground floor. The floor above the ground floor is the first floor, while Americans would call it the second floor.

    The story shows that there are a few culture differences between Britain and America, though the British and Americans both speak English.

    The British usually hide their feelings. They seldom start a conversation with strangers. For example, on the train the British often spend their time reading newspapers or books. But Americans are quite different. They're more active and easier to talk with.

    The British and Americans may use different terms for many things. The British usually use “football”, “eraser” and “mail” while Americans prefer to use “soccer”, “rubber” and “post”.