单选题:Babies often __________down when they are learning to walk. 题目分类:成人英语三级 题目类型:单选题 号外号外:注册会员即送体验阅读点! 题目内容: Babies often __________down when they are learning to walk. A.drop B.fall C.slip D.jump 参考答案: 答案解析: