【单选题】根据短文回答 31~35 题。 A Society Without a Formal Authority In the seventeenth century, European soldiers who came across some Indian groups in the western Great Lakes found that several native tribes(部落)wer...
【简答题】Cell Phones 1.Believe it or not,cell phones have been around for over a quarter of a century.The first commercial cell phone system was developed by the Japanese in 1979,but cell phones have changed a...