Queen's Gambit Declined - 4.Nf3
1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Nf3
White plays the queen's pawn to d4. Black moves the queen's pawn to d5. White moves the c-pawn to c4.
Black advances the king's pawn to e6. White develops the knight to c3. Black develops the knight to f6.
White moves the knight to f3.