单项选择题A．To find articles on ecology.B．To look into some of the specilialized indexes.C．To look for articles published in 297 periodicals.D．To look for articles published from November 10th,1990 to December 28th,2000.

单项选择题A．the US OpenB．the Australian OpenC．the French OpenD．the Hongkong Championship

单项选择题One of the characteristics that have made Mark Twain a major literary figure in the 19th century America is his use of ______.

单项选择题A linguist regards the changes in language and language use as ______.

单项选择题According to the law, children in Britain between the ages of should receive efficient fulltime education.