So don't play 4...f5
English Defence
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After 4.Bd3 (which does not get an !) Black should reply 4...Nc6 attacking the d4 pawn and aiming at going to b4 and exchanging for Whites light squared bishop.
The English Defence was an opening that was used mainly in the 1970s by many leading English players.
It is a slow, quite opening for black designed for fianchettoing the queen's bishop and for early king's bishop and Queen development. It is not very commonly used now as it is more of a one-sided play:3.e4! Bb7 4.Bd3! gives White a large advantage in all continuations. After the further4...f5!? 5.exf5! Bxg2 6.Qh5+ g6 7.fxg6 Bg7 8.gxh7+Kf8, White does not continue with 9.hxg8=Q+ because of ...Kxg8 with a good game for Black, but instead follows with 9.Bg5 Nf6 10.Qh4Bxh1 11.Ne2 and White simply wins this position. Sorry for not being able to show you the end result of the variation but sequence tool had glitch.
References: Chessmaster, Wikipedia