英语将来完成时被动语态：will have been done
“Will have been done” 是英语中一种较为高级的时态结构，属于将来完成时的被动语态。它用于描述在将来某一时间点之前，某事将已经被完成（且强调动作的被动性）。
一、基本结构
肯定句： Subject + will have been + 过去分词 (done)
否定句： Subject + will not (won’t) have been + 过去分词
疑问句： Will + subject + have been + 过去分词?
二、使用场景
该结构常用于以下情况：
- 强调某事将在未来某个时间点前被他人完成；
- 正式书面语或学术写作中；
- 项目进度、工程交付、报告提交等被动结果的预测。
三、经典例句
By next Friday, the report will have been done by the team.
The building will have been completed before the end of this year.
All applications will have been reviewed by the committee by Monday.
Won’t the homework have been done by then?
四、注意事项
1. 主语通常是动作的承受者，而非执行者。
2. 常与 “by + 时间点” 连用，表示截止时间。
3. 不要与主动语态的 “will have done” 混淆。