问题 选择题

下表中“-”表示相连的物质间发生反应,“→”表示这种物质可转化为另一种物质.甲、乙、丙、丁四种物质符

合对应“转化关系”的是(  )

ABCD
转化关系

CNa2CO3NaHCO3Fe
O2Ca(OH)2CaCO3HCl
CuOMgCl2NaOHCuCl2
CO2稀H2SO4Na2CO3NaOH

A.A

B.B

C.C

D.D

答案

A、四种物质中,丙物质氧化铜与丁物质二氧化碳不能发生反应,不符合所给转化关系,故A不正确;

B、四种物质中,甲物质碳酸钠不能直接转化成丁物质硫酸,不符合所给转化关系,故B不正确;

C、甲物质碳酸氢钠丙物质氢氧化钠反应生成碳酸钠和水;碳酸氢钠可以和氢氧化钙反应生成乙物质碳酸钙.丁碳酸钠可以氢氧化钙或者氯化钙反应生成碳酸钙.此四种物质的关系符合所给的转化关系,故C正确;

D、甲物质铁可与乙物质盐酸、丙物质氯化铜发生置换反应,丁物质氢氧化钠可与乙物质盐酸、丙物质氯化铜发生复分解反应,且乙物质盐酸与氧化铜等物质发生复分解反应生成氯化铜,但甲物质铁不能与氢氧化钠反应,因此四种物质不符合所给的转化关系,故D不正确.

故选C.

阅读理解

阅读理解。

     What is the best way to study? This is a very important question. Some of the Chinese students often

 study very hard for long hours. This is a good habit, but it is not a better way to study. I think an efficient

 (有效率的 ) student must have enough sleep, enough food and enough rest. Every day you need to go

 out for a walk. Every week you should visit some friends or some nice places. It's good for your study.

 When you return to your studies, you'll find yourself stronger than before and you'll learn more.

        Some people say that learning English is like taking Chinese medicine. It means that like Chinese

  medicine, the effect of study comes slowly but surely.

1. _____ often study very hard for long hours.

    A. All the Chinese students

    B. Some of the Chinese students

    C. Any of the Chinese students

    D. Only a few Chinese students

2. An efficient student must have_____.

    A. enough sleep      

    B. enough food

    C. enough rest        

    D. A,B and C

3. Every day you need to _____, It's good for your study.

    A. go for a walk

    B. visit some friends

    C. visit some nice places

    D. eat some meat

4. "... learning English is like taking Chinese medicine " means ._____.

    A. it's very terrible

    B. it's wonderful

    C. the effect of study comes slowly but surely

    D. the effect of study comes quickly and surely

5. This passage mainly tells us _____.

    A. you should study hard for long hours

    B. you shouldn't sleep all night

    C. the proper (适当的) way to study

    D. the best way to keep healthy.

选择题