review site and google adsons?

You can try it. If you sign up for Google AdSense you will wait for the confirmation if your site will be approve to have adds on it. So it's not bad to try.

As joebel mentioned, you can if you are approved, but I would think twice before doing that because you'll be loosing your potential customers clicking on google ads (which bring you pennies) instead of buying your affiliate products, which could/should be your main income.

Good question. I'd say it depends on what you're selling, and how you're doing it.

Usually I'd have no problems mixing AdSense with Amazon Asssociates affiliate links, since the payout per sale is usually pretty low anyway (especially in the UK), and a person might just as well click an ad. In such cases, I usually find it beneficial to have both, and the visitor selects for themselves their desired course of action.

If, however, I'm promoting a $97 e-product on which I receive 50% of the sale, the most desirable thing a visitor can do, after (or maybe even before!) buying immediately through my site, is to opt-in to my mailing list.

The last thing I'd want to do in this case is distract the visitor, or have them led away from my site through an AdSense click - worth a penny at worst, and probably a couple of dollars at best - never to return, and to lose the opportunity to have "properly" cashed in on them, and turned them into a loyal, returning customer.

So you really have to be evaluating a number of factors before you can comfortably assume that adding more monetisation options to a site necessarily means it'll have a positive effect on your income (and even then you shouldn't just assume - you should test! ). In some cases, multiple monetisation options can significantly detract from your bottom line.