人生目的是人生的航标，指引着人生的航向
飞机以300m/s的速度水平飞行，该处地磁场的磁感应强度竖直分量为6.0×l0-8T，则长为50m机翼上的动生电动势大小为()
Some doctors claim that a vegetable diet is superior_________a meat diet.
单匝平面载流线圈的面积为0.lm2，通以电流强度为0.4A的电流，该线圈的磁矩大小为______A·m2
The sad condition of women working as house servants around the world received much media_____early this yea
