题目

The rules of our school don’t allow _______ at school. That is to say, nobody is allowed _______ here. to smoke; to B.smoking; smoking C.to smoke; smoking D.smoking; to smoke 答案：D 解析: 略如图是植物根尖模式图，有关叙述正确的是（ ）A．①是吸收水分和无机盐的主要部位B．②处的细胞具有较强的分裂能力C．③处的细胞没有细胞壁D．④具有保护作用，主要由导管细胞构成