1.possibly的基本意思是“可能地”,这词表示对某事不敢肯定或知道得不太清楚,多用于肯定句; 有时还作“无论如何”“不管怎样”“万万”解,多用于否定句。
2.possibly还可作“也许”“或许”解,也可指用来表示非常有礼貌地请别人做某事,提出要求。
3.possibly在肯定句里多与may或will连用,在疑问句和否定句中多与can连用。
4.possibly是强化副词,没有比较等级。

Possibly, this is only one of many answers.这只是许多种合适的答案之中的一种。
You can't possibly walk 20 miles in an hour!你一小时走20英里,这怎么可能!
I was positive that I had seen her before; I could not possibly have made a mistake on that point.我确信我以前见过她,这一点我不可能弄错。
We can't possibly believe the myth of “detente”now.我们现在无论怎样也不相信“缓和”的神话了。
I can't possibly do it.我万万不能。
It may possibly be so.也许是这样的。

possibly, maybe, perhaps, probably
参见perhaps条。
下面两句意思不同:
They can't possibly come today.
他们今天不可能来。
They can't, possibly, come today.
他们今天也许不能来。

［同义词］   at all, haply, in any way, maybe, probably