题目下列代数式−a+b3-\frac{a+b}{3}−3a+b,mπ\frac{m}{π}πm,2x2y2x^{2}y2x2y,353^{5}35,(x−1)2\left(x-1\right)^{2}(x−1)2,S=πr2S=\pi r^{2}S=πr2中,单项式有( )A.111个B.222个C.333个D.444个知识点:多项式章节:数与式 / 整式