题目

In a recent class I was asked “What is a short story?” My first answer was that it was something that could be read in one sitting and brought an illumination（启示）to the reader, sudden and golden like sunlight cracking through heavy cloud．I went on to say that in my opinion a “real” short story was closer to poetry than to the novel． Here are some definitions of the short story．My favorite is Benet's: “something that can be read in an hour and remembered for a lifetime”．One writer said: “the theme of a novel won't fit into the framework of a short story; it如图B-2所示，P、Q是两个电荷量相等的异种点电荷，其中P带正电，Q带负电，它们连线的中点是O，MN是中垂线，两电荷连线与中垂线所在平面与纸面平行，在垂直纸面方向有一磁场，中垂线上一正电荷以初速度v0沿中垂线运动，忽略重力作用，则（      ）A.磁场的方向垂直纸面向外B.正电荷做匀速直线运动，所受洛伦兹力的大小不变C.正电荷做匀速直线运动，所受洛伦兹力的大小变化D.正电荷做变速直线运动，所受洛伦兹力的大小不变