maybe i should send a mail to google and ask them anyway, i wanna know if it's legal to put the ads in a iframe. And manipulate the content with text. example: [adsense code] <body> keywords </body> sorry for my english
No, because you cannot create a page specifically for serving AdSense, which is essentially what you would be doing.
i can't means that if i do it i'll be banned or warned by google? btw i know there are some pages that scan your site looking for keyword or meta tags....but i forgot it if u know of 1 pls tell me
It doesn't mean anything. Google is not obligated to warn you for violating their terms and conditions. They might, but it's not guarantee.