题目按一定规律排列的单项式:xxx,−2x2-2x^{2}−2x2,4x34x^{3}4x3,−8x4-8x^{4}−8x4,16x516x^{5}16x5,−32x6-32x^{6}−32x6,…\ldots…,第nnn个单项式为（ ）A.(−1)n2nxn(-1)^{n}2^{n}x^{n}(−1)n2nxnB.(−1)n+12nxn(-1)^{n+1}2^{n}x^{n}(−1)n+12nxnC.(−1)n+12n−1xn(-1)^{n+1}2^{n-1}x^{n}(−1)n+12n−1xnD.(−1)n2n+1xn(-1)^{n}2^{n+1}x^{n}(−1)n2n+1xn知识点：单项式章节：数与式 / 整式
