问题描述: What is a pen used for? 1个回答 分类:英语 2014-10-17 问题解答: 我来补答 钢笔是用来做什么的?或:钢笔是做什么用的 回答:It is used for writing. 再问: 为什么不是What is a pen used for doing? 再答: be used for doing 结构 be + 过去分词 构成被动语态再问: a pen used for doing What 再答: What is a pen used for doing ? 钢笔是用来做什么的? 展开全文阅读