题目

已知直线l ⊥平面，直线m⊂平面，则“∥”是“l ⊥m”的 A．充分不必要条件          B．必要不充分条件     C．充分必要条件           D．既不充分又不必要条件 答案：AI failed in doing the experiment several times. My teacher suggested ________again.A.to tryB.tryingC.tryD.tried