A：氯水
B：次氯酸钠溶液
C：二氧化硫
D：氯化钙溶液
①空气；②液氧；③四氧化三铁；④高锰酸钾；⑤二氧化碳；⑥自来水；
My old neighbour Charles felt ________ after his children moved out.
有关俄罗斯自然条件的叙述，错误的是( )
When did the boy go to the zoo?
计算：2sin60°+|3﹣2|+12．
