问题 填空题

如图4-9,硬质玻璃管内,左、中、右分别放有3个湿润棉花球;a球浸有溴化钾溶液;b球浸有碘化钾浓溶液;c球中浸有KI淀粉溶液。实验时,从右端缓缓通入氯气,同时在b处微热,并逐渐向左移动酒精灯,则可以观察到:

              

图4-9

(1)在a处有        产生。

(2)在b处有        色产生。

(3)c处变成       色。

(4)稍冷却后,b、c之间的管壁上有       色的        

答案

(1)深红棕色液体 (2)紫 气体 (3)蓝 (4)紫黑 固体

此题巧妙地把卤素间的反应联系在一起,分析时要细心地逐一解决。涉及的反应有Cl2+2KI2KCl+I2,Cl2+2KBr2KCl+Br2,所以在b、c处有碘生成,a处有液溴生成,而碘有升华和遇淀粉变蓝的特性,所以会得上述现象。

选择题

The number of rural(乡村的) left-behind children under 17 years old has increased to 61.02 million, according to a report. These children’s parents leave them with their grandparents or other family members in order to make money in cities.

Sichuan Province and Henan Province have the highest percentage of rural left-behind children. Together with Anhui Province, Guangdong Province and Hunan Province, these five provinces have 43.64% of the country’s rural left-behind children, the report says.

The report finds that left-behind children are mainly in the central and western provinces. But the developed eastern areas also face similar problems, the report says. Guangdong Province has the most left-behind children, with 4.34 million, followed by Zhejiang Province, Jiangsu Province, Shanghai and Beijing.

“What I’m worried about most is the schooling of my child, as I have no time to help her with her homework.” Said An Baiyou, a truck driver from Shangdong Province, who has been leaving his 10-year-old daughter with his parents while driving trucks in other provinces. “However, to make money or to take care of the child, you can only choose one side.”

Wang Zhenyao, the president of Beijing Normal University Institue of Public Welfare, says that if the left-behind children problem can’t be solved, it will affect the nation’s future.

Compared with those who live with their parents, left-behind children need more care and protection. The country should think about ways to attract the rural workers in cities to return and work in their hometown to improve the development of these places.”

In addition, it is important to set up laws to protect the basic rights of young people, especially those with illnesses or only one parent.

These children are the future of the nation. People should offer them their love, care and protection.

小题1:Which of the following is TRUE, according to the passage?

A.Wang Zhenyao has a 10-year-old daughter.

B.An Baiyou chooses to make money in cities instead of taking care of his child in Shandong.

C.Zhejiang Province has about 4.34 million left-behind children.

D.The developed eastern areas don’t have the left-behind children problem.小题2:Wang Zhenyao mainly wants to tell us that ____________.

A.it is not easy to solve the left-behind children problem

B.children with illnesses or only one parent are very poor

C.it is important to solve the left-behind children problem

D.rural workers like working in cities rather than their hometowns小题3:The best title of the passage is____________.

A.Serious facts about rural children

B.A choice of children or money

C.More care to rural left-behind children

D.A report on parents’ worry about rural left-behind children

多项选择题