Google gives old result?

I found old content of my site again after a week I turn to new.

[mann]

Hello,

From last near by 15 days I found that google gives results which is not exactly what I have at my site.

And today G gives me result old result, which I change 7 days before.

Between these days onece or twise G shows exactly as site contained, but today G gives old text again.

Any body know Why?