错误：We will completely have finished the work when you arrive, if you take the 10:05 train.

正确：We will have completely finished the work when you arrive, if you take the 10:05 train.

分析：completely 习惯上要放在所有助动词之后。

我的疑问：上面“分析”中说“completely 习惯上要放在所有助动词之后”是怎么回事？副词不是通常都放在第一个助动词之后吗？