用高铁酸钠（Na₂FeO₄）对河水、湖水消毒是城市饮水处理的新技术。已知制备高铁酸钠的反应为

Fe₂O₃+3Na₂O₂=2Na₂FeO₄+Na₂O，下列说法正确的是 [ ]

A.Na₂O₂既是氧化剂又是还原剂

B.Fe₂O₃在反应中得到电子

C.3 mol Na₂O₂发生反应，有12 mol电子转移

D.Na₂FeO₄能消毒杀菌是因其具有强氧化性

There is a strange smell in your room. You had better keep the window _______. [ ]

A. open

B. opens

C. close

D. closed