断肠之殇材料:what has four legs and only one foot?

What has four legs,but one foot? what has four legs but cannot walk what has four legs but cannot walk? What has four legs(腿) and only one foot(脚)？ what has four legs and only one foot? What has four legs and only one foot ? What has four legs and only one foot ? 四年级孩子的寒假作业,what has four legs and only one foot? It's___. What has four legs(腿) and only one foot(脚)？It's() I'm something that has four legs and only one foot.What am I?