最佳答案:Good manners are very important to everyone.In our lives ,we often heard "Thank
最佳答案:The earth and human beingsWe only have an earth .It like my mother .It gives all
最佳答案:解题思路:若选出的3人中没有甲,方法有C34•A33种.若选出的3人中有甲,方法共有C12•A24种,相加即得所求.若选出的3人中没有甲,方法有C34•A33=