求翻译：一天，一匹小马驮着麦子去磨坊。当它驮着口袋向前跑去时，突然发现一条小河挡住了去路。小马为难了，这可怎么办呢？它向四周望了望，看见一头奶牛在河边吃草。小马问道：“牛阿姨，请您告诉我，这条河我能趟过去吗？”奶牛回答说：“水很浅，刚到膝盖。”是什么意思？

One day, a pony laden with wheat to the mill. When it loaded the pockets ran forward, suddenly found a small river. The colt, how to do it? Looked around and saw a cow grazing nearby. He asked: "Aunt Cow, you tell me that the river can cross in the past?" The cow said: "The water is very shallow, ju