题目

________leaves the room last ought to turn off the lights. A. Anyone            B. The person        C. Whoever         D. Who 答案：C“”是“一元二次方程x2+x+m=0有实数解”的（ ）A．充分非必要条件B．充分必要条件C．必要非充分条件D．非充分非必要条件