题目

Laptop computers are popular all over the world. People use them on trains and airplanes, in airports and hotels. These laptops connect people to their workplace. In the United States today, laptops also connect students to their classrooms.   West lake College in Virginia will start a laptop computer program that allows students to do schoolwork anywhere they want. Within five years, each of the 1500 students at the college will receive a laptop. The laptops are part of a＄10 million computer program at West lake, a 110-year-old college. The students with laptops will also have acce 如图所示，某区域电场线左右对称分布，M、N为对称线上的两点．下列说法正确的是(　　) A．M点电势一定高于N点电势 B．M点场强一定大于N点场强 C．正电荷在M点的电势能大于在N点的电势能 D．将电子从M点移动到N点，电场力做正功