近年来,随着我国经济体制改革的不断深化,许多国有企业纷纷“转轨改制”。许多人以前熟悉的一些国有企业、商店和集体企业不见了,相反,在大街两旁的广告牌和股票市场上,出现了越来越多的“新面孔”。对此,有些人不免心中产生疑惑,认为我国的公有制经济萎缩了,已经不再占主体地位了。

请根据经济生活知识谈谈你对上述疑惑的认识。

某强酸性溶液X含有Ba²⁺、Al³⁺、NH₄⁺、Fe²⁺、Fe³⁺、CO₃^2﹣、SO₃^2﹣、SO₄^2﹣、Cl^﹣、NO₃^﹣中的一种或几种，取该溶液进行迂续实验，实验内容如下：

根据以上信息，回答下列问题：

社会可持续发展的一个重要主题是能源的可持续发展．

先通读下面的短文，掌握其大意，然后在每小题所给的A、B、C、D四个选项中，选出可以填入空白处的最佳选项。

    Good morning, everyone. I want to 1 you about my neighbor(邻居)，Mr. White. There are 2 people in Mr. White's family. Mr. White is a manager of a big shop. Mrs. White teaches English in a university(大学).Her students like her very much 3 she is interesting. The Whites have two 4 . The son is Tim. He is thirteen. The daughter is Nell. She is twelve. There is also a brown 5 in their family. 6 name is Stella.

    Mr. White loves sports and he is good at playing tennis. Mrs. White likes 7 . She draws many beautiful pictures. Tim 8 listening to music. He has many CDs. Justin Bieber is his favorite singer. 9 is Nell's hobby? She likes doing some 10 . She has a lot of books in her room now. On Sunday, then take their cat to the nark and they often have a .good time there.