Black threatens to bring the rook to g2, forking queen and pawn and demanding further concessions from White. White has the opportunity to make some threats, too.
Qa2 threats the pawn on f7. Black must either defend f7 or find something better.
White to move
Some groups are also working through nine problems on a worksheet, many of them decoys (see "Lesson of the Week [19 December 2012]).