题目

 He _______ the information _______ English and wrote a composition. A. searched; in   B. downloaded; about  C. got; from   D. wanted; on 答案：B人造地球卫星的轨道半径越大，则（　　）A．速度越小，周期越小B．速度越小，周期越大C．速度越大，周期越小D．速度越大，周期越大