题目

Books are made __________ paper while paper is mainly made __________ wood.A．of; ofB．from; fromC．of; fromD．from; of 答案：C解析:能看出原材料用be made of；不能看出原材料用be made from，故答案选C。向含有下列离子的溶液中，通入适量的氯气会引起离子浓度减少的是①HCO3- ②SO32- ③OH- ④Fe2+A．①② B．③④ C．①②③ D．①②③④