题目

He is my best friend. I can turn to him for help ________ I get into trouble. A．whatever                                                  B．whenever C．whichever                                                D．however 答案：B如图，在四边形ABCD中，AB∥CD，∠A=90°，AB=5，CD=2．以A为圆心，AD为半径的圆与BC边相切于点M，与AB交于点E，将扇形A﹣DME剪下围成一个圆锥，则圆锥的高为（ ） A.1B.4C.D.