问题 选择题

下列物质的分类正确的一组是

 ABCD
电解质NH3NH4NO3Na2CO3Fe(OH)3
非电解质Cl2CO2HClAl2O3
酸性氧化物CO2SiO2NOCO
HClOH2SiO3CH3COOHHNO3
 

答案

B 

A项,NH3是非电解质,Cl2既不是电解质,也不是非电解质;C项,NO不是酸性氧化物;D项,CO为不成盐氧化物,Al2O3是电解质,故B项正确。注意各类物质的分类方法。

单项选择题
阅读理解

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

(Linguistic(语言学的) Puzzles

     How did language begin? What was the world's first language? Do all languages come from one

original language?   1._____.

     In the 4th century BC, the Greek historian Herodotus wrote this account: Psamtik  I,an Egyptian

King, wanted to find out what the oldest language in the world was.  2.____.He told his servant to find

two newborn babies. When the servant had found them, the king gave them to a shepherd (牧羊人) and

said, "Keep these babies with the goats. Take care of them, but do not talk to them. Listen to any words

that they say." The king wanted to find out what language the children would speak if they were left alone. He said, "The first words they speak will come from the original language of the world."

     3._____  . He told the king who asked his scholars about this word. They told him that the Phiygians, who lived in an area which is now Turkey, called bread "becos".The king said, "Then Phiygian is the

oldest language." Today we know that the king's conclusion was wrong. We don't know why the children

said "becos".

      4._____. Scholars discovered that many European and southern Asian languages belonged to the

same "family" and that they started from the same parent language, ProtoIndoEuropean. Linguists think

that it had split into several different languages, including Greek and Sanskrit, between 2000 and 1000

BC. Other languages, such as English and Spanish, developed from later splits.

     5._____ . Two questions that interest linguists are: How does language change? Why does language

change? If you like solving mysteries, historical linguistics may be the job for you.

A. Nowadays, we study the origin of language more scientifically

B. He was talking about this problem with his scholars when he had an idea

C. The King was very kind to his servant and his servant remained royal to him

D. Linguists are the scholars who are very interested in categorizing the language families

E. People have been trying to find the answers to these questions for more than 2000 years

F. One day, while the babies were babbling to each other, the shepherd heard them say "becos"

G. Linguists have classified many language families, and they are still trying to categorize others