铁磁性材料磁化后，在不连续处或磁路截面变化处，磁感应线离开和进入表面时形成的磁场叫做（）。
参考答案：漏磁场
Having finished her project, she was invited by the school ________ to the new students.[ ]
A. speaking
B. having spoken
C. to speak
D. to have spoken
弹簧回转数与出力两组变量之间的相关性为（）。
A.强正相关
B.强负相关
C.弱正相关
D.曲线相关
