念念念念的不过是过去想想想想的不过是回忆
[niàn niàn niàn niàn de bù guò shì guò qù xiăng xiăng xiăng xiăng de bù guò shì huí yì]
The repetition here emphasizes obsession with the past; roughly it can be translated into: 'What we keep thinking about is nothing but the past, what we always recall is nothing more than memories.' It signifies a lingering in reminiscence rather than focusing on present or future.