Complex sentence: Although 4.Qa4 corresponds to a fairly commonly played variation of the Scandinavian Defense (1.e4 d5 2.exd5 Qxd5 3.Nc6 Qa5), it is rarely played in the Center Game because tournament experience has not been favorable for White in this line.
Split into simpler sentences: Although 4.Qa4 corresponds to a fairly commonly played variation of the Scandinavian Defense (1.e4 d5 2.exd5 Qxd5 3.Nc6 Qa5), it is rarely played in the Center Game. Tournament experience has not been favorable for White in this line.