下列各物质的化学式、对应的名称（或俗名）、物质所属的类别都正确的是（ ）
A．Fe2O3 氧化亚铁 碱性氧化物
B．CO2 二氧化碳 酸性氧化物
C．H2SO3 硫酸 酸
D．Na2CO3 纯碱 碱
A、Fe2O3 名称为氧化铁属于碱性氧化物，故A错误；
B、CO2名称为二氧化碳属于酸性氧化物，故B正确；
C、H2SO3 是亚硫酸，属于酸，故C错误；
D、Na2CO3 俗称纯碱，属于盐，不是碱，故D错误；
故选B．
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| "So teach him to close the door", my daughter Emma responded after listening to me 1 , again, about the dog coming in from the back door, bringing with him a blast of Buffalo January 2 air. Teach a dog to close a door behind him? That has got to be a really, really 3 thing to do. But then she took a step 4 . "Come on, Kolby", she said, grabbing some treats (犒劳物) and 5 him in front of the open door. "Touch." And "touch" he did, which moved the door to a 6 position. She 7 him with a treat, smiled, looked at me, and said "see!" And I saw and became 8 . Over the last few days I have been with Kolby. Each time he comes in I bring him back to the 9 door and ask him to close. There have been 10 in the beginning, but lately more and more successes. However, there remains much work to be done. I have to get him to follow my hand signal again and again 11 he will close the door from a distance. But, I now realize, 12 you keep to the focus, the 13 will be completed. What a 14 treat to have a dog that can close the door after himself! Even more wonder can be found in the 15 I learned so clearly from both Emma and Kolby. A wish is just a wish until you decide to take 16 . Once you 17 the belief that it is "too hard", then it remains "too hard" and out of 18 . Once you want to accomplish a goal, and 19 that it is "easy", then it becomes "easy" to do what needs to be done. Just 20 doing it. | ||||
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