Queen's Gambit Declined - semi-Slav - Marshall gambit
1. d4 d5 2. c4 e6 3. Nc3 c6 4. e4
White moves the queen's pawn to d4. Black advances the queen's pawn to d5. White plays the c-pawn to c4.
Black pushes the king's pawn to e6. White develops the knight to c3. Black advances the c-pawn to c6.
White plays the king's pawn to e4.