已知等腰三角形的两条边长分别是7和3，则此三角形的周长为____ 

如图，AB∥CD，EG⊥AB于G，∠1=50°，则∠E =____.

外交是一个国家综合国力的体现，加强对外交往有利于国家发展和民族振兴。阅读下列材料，回答问题。

材料一　朝贡外交是中国古代王朝特有的一种外交体系…………自商周以来，中原王朝都认为自己居天下之中，是“天朝上国”，凡要与中原王朝建立关系、展开外交者，必须以朝贡方式进行……朝贡外交走进历史博物馆同列强将不平等条约强加在中国头上分不开，也就是说，是不平等条约迫使当时的中国政府不情愿地接受了现代外交。

——《不平等条约的另一面：推进中国融入全球化历史进程》

材料二　1972年2月21日，美国总统尼克松访华，与***、周恩来等新中国第一代领导人一起，共同打破了中美两国关系的“坚冰”，成为20世纪影响国际关系格局的最深远事件之一。

——周正平、刘东凯《冀朝铸：见证中美关系史上关键时刻》

材料三　20世纪80年代，中国领导人开始接受国际贸易中“国际分工”的理念，认识到在国际市场上开发自身“比较优势”的重要性。东亚“四小龙”的出口导向型发展战略为中国提供了效仿的榜样。中国几乎同时与所有的国家改善关系，加强了与世界市场的交往和联系。

——摘编自郝雨凡《中国对外经济政策50年》

    Not everyone has a chance to be a detective（侦探）, but I got one when I was 13 years old. It happened in 1994.
One afternoon, I was walking down the street when I saw my father's new car. I expected(期望) to see my father in the driver's seat. But to my surprise, I saw a young woman driving instead, “She has stolen my father's car,” I thought. So I quickly stopped a taxi and got in. I said to the driver, “Follow that new car in front,” I told him why.
    The taxi driver had a car phone, so I asked him to call the police. Soon we heard the sound of a police car. The police told the woman to stop the car using a loudspeaker. The taxi came to a stop, too. I got out right then and said to the woman, “This is not your car. It's my father's car.”
The woman smiled and said, “Oh. You're Mr. Johnson's son, right? I've seen your photo in your father's office.”
    Before I could say one word, the woman explained that she was my father's new assistant（助手）. My father had asked her to take his computer to the shop to have it repaired. He lent her his car. After hearing this, I called my father and he told us what the woman said was right. The police and the taxi driver laughed. I felt very sorry. It was both the first time and the last time I worked as a detective.