至少有两张黑桃即两张黑桃,三张黑桃,四张黑桃P(两张)=C(13,2)*C(52-13,2)/C(52,4)=4446/20825P(三张)=C(13,3)*C(52-13,1)/C(52,4)=858/20825P(四张)=C(13,4)/C(52,4)=11/4165P(总)=5359/20825=0.257334934