英语高手进来一下！！！！！！！

Pure substances mean that they are made of only one substance, which can be an element or a compound. For instance, diamond is pure,it contains only carbon atoms. , distilled water is pure, it contains only H2O. Ordinary, there are few pure substances in our daily life. You may say that most metals are pure,like cupper wire,as well as iron nails. But, strictly speaking ,these two substances contains also very little amount of inpurities

初中化学的知识啊：单质、化合物、混合物。
你只要把这3个概念的本质搞清楚了，也就不存在问题。举例就免了，人要是太懒，是很难学好东西的，所以自己去多想想。

这个是你看见确切的句子了吗
人家写成wonna
还是你音译过来的
如果你想表达你说的意思
wanna就可以了
wonna在苏格兰英语中可是
will
not的意思呀

楼主 这个要求有点难
我化学不好 就算知道纯物质 化合物 混合物
也不能用百度找到20个。。