下列离子方程式表达正确的是（ ）
A．用惰性电极电解熔融氯化钠：2Cl-+2H2O
Cl2↑+H2↑+2OH- 通电 .
B．用氢氧化钠溶液除去铝表面的氧化膜：Al2O3+2OH-═2AlO2-+H2O
C．用稀氢氧化钠溶液吸收二氧化氮：2OH-+2NO2═NO3-+NO↑+H2O
D．用食醋除去水瓶中的水垢：CO32-+2CH3COOH═2CH3COO-+CO2↑+H2O
A、熔融氯化钠中没有水分子，只有钠离子和氯离子，则电解熔融的氯化钠生成钠和氯气，故A错误；
B、氧化铝是两性氧化物，可以和强碱反应得到对应的盐和水，故B正确；
C、二氧化氮是酸性氧化物并具有氧化性和还原性，稀氢氧化钠溶液和二氧化氮反应的产物有硝酸钠、亚硝酸钠及水，离子方程式中电荷不守恒，故C错误；
D、水垢中的碳酸钙是难溶物，不能拆成离子形式，应用分子式，故D错误．
故选B．
In Renee Smith's classroom, attendance is up. Trips to the headmaster's office are down and students are handing in assignments on time. The Springfield High School teacher says she has seen great __1__ since adding a few new students to her class―five Labrador puppies and their father. The seven __2__ students in Smith's class have a history of discipline __3__. But since they've started teaching the dogs obedience (顺从), their own __4__ has improved. A dog trainer Chuck Reynolds __5__ the students a new trick each week that they then workon with the puppies. At night, the dogs go home with the staff members who have raised them. They get dropped off in the morning, __6__ a parent would take a child to day care. Smith said she came up with the idea when her dog had puppies and she say, how __7__ her own children responded to them. She consulted with school psychologist Kristin Edinger, __8__ they took the idea―along with letters from students __9__ the program ―to the school board. A pet therapist said, "What you are trying to teach is __10__ and that thereare consequences for the decisions you make."
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