意为永远,总是.
二者是通用的.
例如:1.You'll never get that ball back - it's lost forever( for ever).你再也找不回那个球,永远也找不回来.
2.Why are you forever asking questions?你为什么老是问问题啊?
楼上说得也很好,的确一个是形容词,一个是副词,而且更确切一点,是副词词组.
没有区别
有
forever(adj.)形容词做前置定语;for ever(adv.)修饰动词,常用于句末,试比较:
I have a forever family.
I love you for ever.
one is a.
the other is ad.