will have been后面的动词是什么形式的？

过去分词或现在分词都可以
即done 或 doing
will have been done是将来完成时的被动
如：The museum will have been built by 2010.
到2010年时，这个博物馆就已经盖好了。

will have been doing是将来完成进行时。
如：By the end of next weekend,he will have been learning English for 3 years.
截至到下个周末，他就已经学英语学了三年了~

will have been done 为将来完成时
will have been doing 为将来完成进行时

done
将来完成时

done/doing

动词的过去分词语态。如will have been done