题目

必须加入还原剂才能实现的反应是                                      （    ）     A．KCIO3 →O2         B．Fe2+→ Fe3+      C．SO2 →S     D．CO32— →CO2 答案：CI often have noodles for ________ breakfast and I usually have ________ big breakfast. A．不填; 不填 B．不填; a C．the; a D．a; 不填