问题 选择题

下列实验操作及现象与结论正确的一组是[ ]

实验操作  
实验现象
实验结论
A.适量二氧化碳通入氯化钙溶液中  产生白色沉淀碳酸的酸性比盐酸弱
B.二氧化硫通入石蕊溶液中 溶液先变红后褪色 二氧化硫有酸性和漂白性
C.取少量无色溶液,先加少量硝酸,再
加少量的四氯化碳,振荡、静置  溶液分层,下层为无色原无色溶液中一定不含碘离子
D.蔗糖中滴入浓硫酸和几滴水,并用玻
璃棒搅拌  蔗糖变黑,体积膨胀,
并放出刺激气味的气体浓硫酸有脱水性和强氧化性
答案

答案:D

选择题
阅读理解

任务型阅读。

     阅读下列短文,根据所读内容在文章后的表格中填人 恰当的单词。

     注意:表格中的每个空格只填1 个单词.

    The farm economy of the United States has changed a lot in the last seventy years. In the 1930s,

twenty-five percent of the nation's population lived on farms. Today less than one percent of Americans

do.

       Farm incomes have changed over the years, too. For example,in 1933,people living and working on

farms had much less money to spend than other Americans. At that time,farm families had about one-third

the income of non- farmers after all necessary expenses had been paid. By the late  1970s, however, that  difference  had  almost disappeared. In 2004,farmers had their best year ever. The average farm family

earned about eighty-one thousand dollars. That was more than the average American family, which

earned about sixty thousand dollars.

   The Department of Labor measures the pay of industrial workers differently. It measures the average

hourly and weekly pay for industrial workers. This is because factory workers are generally paid by the

hour unlike farmers who earn income from their farm businesses. Generally, the average hourly pay for

all

industrial workers is about sixteen dollars. And the average weekly pay,about five hundred fifty dollars.

     Industrial workers were about twenty-three percent of the labor force in the 1970s. But that number

has been decreasing. Most Americans have jobs that provide services. Professional,technical and other

services employ about eighty-six percent of the labor force.