题目

Young ___ he is, ___ he can do the job much better than others. A．although, however                                      B．though, but             C．while, still                                D．as, yet 答案：D利用数学归纳法证明不等式1n+1+1n+2+…+1n+n＞12（n＞1，n∈N*）的过程中，用n=k+1时左边的代数式减去n=k时左边的代数式的结果为 ．