题目

When she heard from the hospital that her father had died, she _____ into tears.A. burst       B. went       C. exploded       D. fell   答案：Aburst into tears放声大哭;又如：burst into thunderous cheers(发出雷呜般的欢呼);burst into laughing(捧腹大笑)。（09年宿迁市学业水平测试）在赤道附近的地磁场可看做是沿南北方向的匀强磁场，磁感应强度的大小是0.5×10－4T。如果赤道上有一根沿东西方向的直导线，长20m，通有从东向西的电流30A，问地磁场对这根导线的作用力为__________,方向为_________。