将来完成时的疑问

Question

根据定义，将来完成时是：主语 + shall (will) have + 过去分词 构成

不过我看到有将来完成时句子在have后还有been，例如：
They will have been graduated from the university before 2008.

The project to clear up the polluted river will have been completed by the end of next year.

这些句子为什么是 will have been done的结构的呢？与定义上的结构有什么区别？应该在什么情况下使用带“been”的结构呢？

谢谢各位的解答。

Answer 1

你所说的属于将来完成时的被动语态，即基本结构为：sb. /sth. will have been done + 表将来的时间. 其中，主语是后面谓语动作的承受者，两者之间存在着被动关系， will have been 表将来完成，been done 表被动。
They will have been graduated from the university before 2008.
他们将在2008年前被授予大学学位或毕业文凭。（此话说在2008年前）
The project to clear up the polluted river will have been completed by the end of next year.
治理污染河流的工程将在下一年底完成。

Answer 2

第一句话当且仅当这句话是2008年之前说的才对。而且have been graduated的说法很少见，一般说graduate都是学生（主动）毕业这样的。
They will have been graduated from the university before 2008.
他们在2008年之前（含义：现在还没到2008结束），将从大学毕业。

The project to clear up the polluted river will have been completed by the end of next year.
到明年底之前，这个治理污染河流的项目将全部完成。

以上两句都是将来完成时，你举的主语 + shall (will) have + 过去分词 构成是指主语主动完成这个动作，当主语是被完成时，要用被动式，则为主语 + shall (will) have + been 过去分词

希望对你有所帮助。

Answer 3

Will they have been graduated from the university before 2008?
Will the project to clear up the polluted river have been completed by the end of next year?
为表示将来时
（请具体指出哪种时态）
表示将来时、现在将来时可运用本回答被网友采纳