摘要: 题目 An army of ants walk on a horizontal pole of length l cm, each with a constant speed of 1 cm/s. When a walking ant reaches an end of the pole, it i 阅读全文
posted @ 2020-04-15 07:33 liuzhaoxu 阅读(218) 评论(0) 推荐(0) 编辑