My movie site shows untargeted ads, about 70% of the ads shown from adsense is untargeted, means they show ads not about movies and so. Does it take weeks for google to understand each sites content and deliver ads according to the themes of them or should I be worried?

Also, when i search for "film reviews" it shows 0 results on result page from my search engine but when i search for "movie reviews" and other search terms it shows many results. Why is that? On google.com results are many for "film reviews".

Thanks for any answer

The pages have to be indexed by Google before the ads become "relevant", so yes it can take several weeks