问题描述: yangliwei spent about twenty-one hours in space.改成否定句疑问句回答 1个回答 分类:英语 2014-10-14 问题解答: 我来补答 否定:Yangliwei ddn't spend about twenty-one hours in space.疑问:Did yangliwei spend about twenty-one hours in space?Yes, he did. 或No,he didn't. 展开全文阅读