阅读文章并回答以下问题

     Do you live in a city? Do you know how cities began? Long long ago, the world had only a few thousand people. These people moved from one place to another. They moved over the land, hunting animals for food. No one knows how or when these people learned about growing food. But when they did, their lives changed. They did not have to move houses any more. They could stay in one place and grow it. People began to live near each other, so the first village grew. Many people came to work in the villages, and these villages became larger and larger. Then people had machines, life in the villages changed again. People built factories. More and more people lived near the factories. So the villages grew into cities. Some of them grew very big. Today, it’s strange that some people are moving back to small villages. Can you tell me why ?

am+bm=m(____)

实验一：配制并标定醋酸溶液的浓度

取冰醋酸配制250mL 0.4mol/L的醋酸溶液，用0.4mol/L的醋酸溶液稀释成所需浓度的溶液，再用NaOH标准溶液对所配醋酸溶液的浓度进行标定．回答下列问题：

依次填入下面一段文字横线处的语句，衔接最恰当的一组是(   )
在我们生存的这个地球上，恐怕没有哪个民族像中华民族一样，对土地怀有如此恒久深厚、无法割舍的情结。            ，              。                ，          。         ，         。“人间珠玉安足取，岂如阳羡溪头一丸土”这句名言，是清代诗人汪文柏赞美宜兴紫砂陶土的诗句。
①陶土之精华紫砂，融工艺与人文之精髓而成
②从土地里升华起来的中华文明
③当代著名诗人艾青的传世名句“为什么我的眼里常含泪水，因为我对这土地爱得深沉”
④而陶器中堪称千年国粹的当数宜兴紫砂壶了
⑤就是对这一“中华民族土地情结”生动而艺术的诠释
⑥其中与土地结合最紧密、也是最具有特色的文明产物，除了中华瓷器之外就是陶器了