问题 填空题

硫酸和盐酸既是实验室常用的试剂,也是重要的化工原料。它们既有相似之处,又有不同之点。

(1)从组成上看,两者的不同点是______。

(2)它们都能除铁锈,写出硫酸与铁锈主要成分反应的化学方程式 __________此实验的现象是_______________。      

(3)它们都能与碱反应生成盐和水,该类反应叫___________反应。      

(4)打开两瓶分别盛有浓硫酸和浓盐酸的试剂瓶,瓶口出现白雾的是_____。

答案

(1)酸根离子不同  

(2)Fe2O3 + 3H2SO4 === Fe2(SO4)+ 3H2O ;  铁锈消失,溶液由无色变成黄色  

(3)中和

(4)浓盐酸

阅读理解

If we are asked exactly what we were doing a year ago, we might have to say that we could not remember. But if we had kept a book and written in it an account (陈述) of what we did each day, we should be able to give an answer to the question.

It is the same in history. Many things have been forgotten because we do not have any written account of them. Sometimes men did keep a record of the important happenings in their country, but often it was destroyed by fire or in a war. Sometimes there was never any written record at all because the people of that time and place did not know how to write. For example, we know a great deal about the people who lived in china 4,000 years ago, because they could write and leave written records for whose who lived after them. But we know almost nothing about the people who lived even 200 years ago in central Africa, because they had not learned go write.

Sometimes, of course, even if the people cannot write, they may know something of the past. They have heard about it from older people, and often songs and dances and stories have been made about the most important happenings, and those have been sung and acted and told for many generations, for most people are proud to tell what their fathers did in the past. This we may call ‘remembered history’. Some of it has now been written history, because words are much more easily changed when used again and again in speech than when copied in writing. But where there are no written records, such spoken stories are often very helpful.  

小题1: Which of the following ideas is NOT talked about in the passage above?

A.“Remembered history” is less reliable than written history.

B.Written records of the past played a most important in our learning of the human history.

C.A written account of our daily activities helps us to remember what we have done

D.Where there are no written records, there is no history.小题2:Remembered history”refers to          .

A.history based on a person’s imagination

B.stories of important happenings passed down from mouth to mouth

C.history written down in books

D.what we have learned and remembered in history lessons小题3:“Remembered history”is regarded as valuable only when       .

A.it is written down

B.there is no written account

C.is proves down

D.people are interested in it小题4: It can be inferred from the passage that we could have learned much more about our past than we do now if our ancestors had      .

A.kept a written record of every past event

B.not fought against one another in wars

C.told exact stories of the most important happenings

D.produced and taught more songs and dances

判断题