某工业废水中可能含有Fe²⁺、Cu²⁺、Fe³⁺、NO₃^﹣、Cl^﹣中的两种或多种．下列结论正确的是（　　）

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    Mr. Wu is having a class in Class Five．He is asking students to think about(思考)  1  future 1ife．Here are some students' opinions(观点)．  

    Zhang Wei thinks people will live in the2like fish．because in the future people will 3organic silicon(有机硅)to breathe(呼吸)in the sea．And people will build 4and schools in the sea．Then they can see doctors and go to school．He

thinks life in the sea will be very 5  and comfortable．

    Luo Li thinks  6 in the future will be great．Every family will have a car．And these cars will 7  in the sky．People will drive cars to their offices．

  Wang Kai thinks machines like robots will do work for people,   8  people will have more 9  time to enjoy life．He thinks people will have short winter holidays but long  10holidays because the summer will be very long．