题目

 --- What pleasant weather! Shall we go boating on the lake? --- _______. A. That’s right                                     B. Thank you very much C. It doesn’t matter                              D. Sounds great 答案：D如图，在杨辉三角形中，从上往下数共有n(n∈N*)行，在这些数中非1的数字之和是________．