Queen's Gambit Accepted - Mannheim variation
1. d4 d5 2. c4 dxc4 3. Nf3 Nf6 4. Qa4+
White moves the queen's pawn to d4. Black advances the queen's pawn to d5. White pushes the c-pawn to c4.
Black captures on c4 with the queen's pawn. White develops the knight to f3. Black develops the knight to f6.
White moves the queen to a4, giving check.