Chess Opening Theory/1. e4/1...e5/2. Nf3/2...d6/3. d4/3...Nd7/4. Bc4/4...Be7

4..Be7
This natural move immediately loses a pawn, 4...exd4 is preferable. The only move that wins a pawn is dxe5. The Hanham variation with 3...Nd7?! is full of traps, which is why 3..Ngf6 is more common.