目前人类已发现几千万种物质,对物质进行分类,有利于我们的学习.下列物质的分类不正确的是( )
A:SO2(氧化物)
B:碘酒(单质)
C:HNO3(含氧酸)
D:氯水(混合物)
①溶液质量增加 ②溶质质量增加 ③溶剂质量不变
④晶体质量不变 ⑤晶体质量减少
如图所示,一个足球静止在水平地面上,请画出它受力的示意图
I've become good friends with several of the students in my school _______ I met in the English speech competition last year.
---Yes, they are very popular among young people.
Mike is a bus driver. (变为一般疑问句)
____