forever，for ever 这两个意思都是永远，永久。但是用法上是有区别的。
forever可以放在句末做状语，也可以放在句中修饰动词。而for ever只可以放在句末做状语。
拓展资料
forever
1、BrE also for ever
永远
used to say that a particular situation or state will always exist
I'll love you forever!
我永远爱你！
After her death, their lives changed forever.
她死后他们的生活从此改变了。
Just keep telling yourself that it won't last forever.
要不停地提醒自己，这不会永世长存的。
2、BrE also for ever
(informal) 长久地
a very long time
It takes her forever to get dressed.
她穿衣打扮要用好长的时间。
3、(informal) （与动词进行时连用）老是，没完没了地
used with verbs in the progressive tenses to say that sb does sth very often and in a way that is annoying to other people
She's forever going on about how poor they are.
她老是没完没了地讲他们有多穷。
for ever
1、I know I shall feel for ever in her debt.
我知道我将会永远感激她。
2、It was great fun but we knew it wouldn't go on for ever .
这很开心，但是我们知道不会永远这样。
3、You can't run away for ever.
你不能永远逃避。
4、Lulled by almost uninterrupted economic growth, too many European firms assumed that this would last for ever.
近乎持续的经济增长使许多欧洲公司误以为会好景长在。
5、They will bitterly regret what they have done for ever more .
他们会为自己的所作所为痛悔终生。