三种情况,语文2本,数学2本和英语2本C42*C51*C61+C41*C52*C61+C41*C51*C62=180+240+300=720
C(4)(2)C(5)(1)C(6)(1)+C(4)(1)C(5)(2)C(6)(1)+C(4)(1)C(5)(1)C(6)(2)=720
C41*C51*C61=120