I'm going to Beijing this summer vacation with my family. We're going there by train. We're going to stay in a hotel. We're going to see the Great Wall, the Bird's Nest. We're going to see Tianan'men square, too. I'm
两个不等幅的脉冲波在均匀介质中均以1.0m/s的速率沿同一直线相向传播,t=0时刻的波 形如图所示,图中小方格的边长为0.1m,则以下不同时刻,波形正确的是( )
党的“十八大”报告中提出了进一步加强教育均衡发展。下面措施中最早体现均衡教育思想的是( )