宋朝是当时世界上从事海外贸易的重要国家。为加强对海外贸易的管理，宋朝政府（    ）

阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或者使用括号中词语的正确形式填空。

Mr Jones had a few days’ holiday, so he decided to go on a trip. He put  ____ his best clothes, took a small bag, ____(go) to the train station and got on the train. He had a 18. ____(beauty) hat, and he often put his head out of the window ____(see) the mountains during the trip. Suddenly, the wind  ____(blow) away his hat.

  Mr Jones  ____(quick) took his bag and threw it out of the window.. ____(other) on the train laughed and said, “Is your bag going to bring your hat  ____?”

  “No,” Mr Jones answered, “but there is no name or address on my hat, and there ____(be) a name and ____ address on the bag. Someone will find both of them, and he will send the bag and the hat back to me.”

已知一个等腰三角形的一边长是3，另一边长为7，则这个等腰三角形的周长为（   ）