题目

禁止随地吐痰从预防传染病的措施分析是为了（    ） A．控制传染源       B．切断传播途径     C．保护易感人群     D．阻截病原体 答案：BEvery time _______ I come across difficulties, I will turn to my parents for help. A．/ B．when C．that D．which