选择序号填在相应横线上：

①铁矿石；②过氧化氢：③水；④食醋；⑤氯酸钾：⑥水银；⑦澄清石灰水；⑧高锰酸钾；⑨氧化铜：⑩硫酸钡．

其中混合物：____；

氧化物：____．

阅读理解

Name: Kelsey

Age: 22

I can sing and dance. I can play the violin and the piano, but I can't play the guitar.

Name: Paul

Age: 13

I can sing, but I can't dance. I can play the trumpet and the guitar but I can't play the violin.