问题描述: at the age of three 和 by the age of three有什么区别 1个回答 分类:英语 2014-10-07 问题解答: 我来补答 at the ageof three表示在3岁时,后面主句一般用一般时态; by the age of three强调到3岁为止,后面主句一般用完成时态. 展开全文阅读