“Avatar” is expected to retain its death grip on the box-office for a sixth consecutive week, though experts disagree over exactly how much of a Golden Globes bounce it will receive, with forecasts ranging from $28 to $40 million. There is unanimity, however, that Fox will also own the No. 2 slot with “The Tooth Fairy” forecast to open around $20 million. Dwayne Johnson’s last family-oriented sports comedy, the better-promoted “The Game Plan,” bowed to $22.9M for Disney, and this one’s campiness should also appeal to The Rock’s large gay fan base. As should co-star Julie Andrews, making her first appearance for Fox since the Gertrude Lawrence musical bio-pic “Star” nearly turned the studio into a subdivision back in ’68 (her other Fox title, “The Sound of Music” is still the No. 2 grossing film of all time if you adjust for inflation). Fox is lucky that reviews don’t matter much for this kind of movie; it’s scoring 12 percent favorable notices at Rotten Tomatoes, which like Fox and The Post is a unit of The News Corp. Third place looks like a battle between a pair of apocalyptic thrillers that prognosticators expect will be duking it out in the mid-teens. The incumbent is Warners’ “The Book of Eli” and the newcomer is Screen Gems’ “Legion” with Paul Bettany and Dennis Quaid. The latter was not screened in advance for print critics, but all six of the fanboy blogger sites quoted at RT give it a fat thumbs down. “Boring, slow paced,” complains Bloody Disgusting, while Dread Central calls it “Shockingly bad.”Fifth place looks like a duel between Paramount and its former corporate sibling CBS, which is back in the theatrical film business for the third time over the past four decades. I give 2 stars to CBS’ inaugural effort “Extraordinary Measures,” which plays like a TV disease-of-the-week flick despite the presence of Harrison Ford and Brendan Fraser, who typically draw very modest numbers outside of genre fare. It’s said to be tracking best among over-35 females, which unfortunately is the audience segment most likely to be put off by the poor reviews — 26 percent at RT. “Extraordinary Measures” is forecast to arrive at just under $10 million, roughly the same territory as Paramount and DreamWorks’ holdover “The Lovely Bones.”