4. The geographic core, in Twain’s early years, was the great valley of Mississippi River.
5. He was a man who became obsessed with the frailties of the human race, who saw clearly ahead a black wall of night.
6. His popularity is attested by the fact that more than a score of his books remain in print, and translations are still read around the world.
8. 世界历史课使我们对埃及的古代文明有所了解。The world history course has ___ ___ ___ ancient civilizations of Egypt.