已知S k =1 k +2 k +3 k +…+n k ,当k=1,2,3,…时,观察下列等式: S 1 = n 2 + n, S 2 = n 3 + n 2 + n, S 3 = n 4 + n 3 + n 2 , S 4 = n 5 + n 4 + n 3 - n, S 5 =An 6 + n 5 + n 4 +Bn 2 ,… 可以推测,A-B=________.
【简答题】If they are not sincere and do not practice what they preach(说教), their children may become confused, and emotionally insecure when they grow old enough to think for themselves and realize they have b...