Mayme Clayton collected books， magazines and letters written by African Americans. Her son， Avery Clayton， thought her collection was important. Unlike most books， these were rare and hard to find. They were written by writers who helped shape African American culture.

    One book in the collection was written by Phillis Wheatley. Wheatley was a slave who wrote poetry. She was the first African American to publish a book. Wheatley herself signed (签名) the book in the Claytons' collection. No one else owns a copy signed by Phillis Wheatley.

    By the time she passed away at age 83， Mrs. Clayton had more than 30，000 books by or about black people. Her collection also includes papers about slaves， photographs， movies， sheet music， and personal letters by black leaders and artists. It is one of the biggest personal collections of African American history and culture in the United States.

    Avery Clayton's dream was to create a museum for his mother's treasures.  Scholars say that Mrs. Clayton's collection is very important. Without her work， part of African American heritage (遗产) would have been lost. “We didn't know these things existed，” says Sara Hadron of California's Huntington Library.

    The collections new home is likely to be in Culver City， California. Part of Avery Clayton's dream is to share the cultural riches his mother collected with others. He especially wants children to have a chance to see the collection. “ At present African American culture is being explained by pop culture，” he says， “ It's important to offer a more complete picture.”

我国是海洋资源极为丰富的国家，品种繁多，共有海洋生物20278种，占世界海洋总数的25%以上，请据图回答：

（1）图一中的生物和环境共同构成____ ．

（2）图一、图二的7种动物中属于无脊椎动物的是____ ，其中溢圣属于____ ．

（3）这7种动物中为胎生、哺乳的是____ ．

（4）近年来，海洋资源开发、轻保护，生态环境严重受损，请提出保护生态环境的合理建议____ ．

目前，美国接受一批中国、印度等国的科技人才和著名学者迁入．影响该人口迁移的主要因素是（　　）

苏东坡是宋代的文坛巨匠,在当时的政治舞台上也颇有建树。他提出通过减免零售商的赋税来刺激商业的发展,以增加政府的商税收入。苏东坡的税收思想肯定了（  ）

①税收是财政收入的重要来源　②税收是实现公平的有效手段　③税收是调节经济的重要杠杆　④税收应该取之于民,用之于民