题目

--- I hear you        at Smith’s.     --- Yes, I       there for about three months.        A．work; had been working         B．worked; was working        C．are working; have been working            D．worked; have worked 答案：C下列关于组成细胞化合物的叙述，不正确的是（  ）A．蛋白质肽链的盘曲和折叠被解开时，其特定功能并未发生改变B．RNA与DNA的分子结构相似，由四种核苷酸组成，可以储存遗传信息C．DNA分子碱基的特定排列顺序，构成了DNA分子的特异性D．胆固醇是构成细胞膜的重要成分，在人体内参与血液中脂质的运输