题目

 New policies _______ to insure that compulsory education is truly free ________ by the local government across China since the start of school on September 1st, 2011 A. intending; have been made to know           B. intended; have been made known C. intended; have been made to be known        D. intending; have made to be known 答案：B上海盛绿等食品公司，向面粉中添加柠檬黄（混有铬酸铅，化学式为PbCrO4）制作“染色”馒头．食用“染色”馒头会对人体造成危害．已知铬酸铅中铅元素的化合价为+2价，则铬元素（Cr）的化合价为（ ）A．+6B．+4C．+2D．+1