400-600-1123
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答案：
B
C(2，1)C(2，1
)/A(4，4)
随机挑花排序所以是A(4，4),
然后它说中间两个位置是红花的概率。
假设四个位置分别为1、2、3、4.
种第1个位置时，只能种白花，白花有2朵，所以是2选1，C(2,1)=2
种第2个位置时，只能种红花，那么只有在2朵红花里面选一朵来种，也是2选1，C(2,1)=2
种第3个位置时，只有1朵红花可以选了，所以是C(1,1)=1
种第4个位置时，因为也只剩一朵花了，也是C(1,1)=1
所以中间是红花的的选法有2x2x1x1=4
所以4/24=1/6，选B。 
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