转换成疑问，否定

解题思路： 如下
解题过程：
①我去过那个美丽的岛一次
I have been to that beautiful island once 。
Have you been to that beautiful island once ?
I haven't been to that beautiful island once 。
②我哥哥听说过那个著名的人名
My brother has heard of that famous name 。
Has your brother heard of that famous name ?
My brother hasn't heard of that famous name 。
③他们刚刚丢失了一本书
They have just lost a book 。
Have they just lost a book ?
They haven't just lost a book 。
最终答案：略