不同地区间的经济不平衡economic inequalities between different areas鲍尔曼曾研究过道格拉斯冷杉种子产量地区间的差异.Bolman has studied regional variation in Douglas fir seed yields.置信限是指置信区间的界限.Confidence limits are the upper and lower limits of the confid...
We know about magnetism by the way magnets act.我们通过磁铁的作用知道磁性是怎么一回事.The N pole and S pole of two magnets will attract each other.两个磁体的N极和S极互相吸引.The entire ring has about 1000 magnets spaced at regular intervals.整个圆环由大约100...