问题 选择题

为确定某一因素对物质溶解性的影响,A、B、C、D四个实验中能与实验I作为一组达到实验目的的是            

实验编号温度溶剂种类溶剂体积加入固体质量溶解情况
实验I20℃10 mL5 g硝酸钾部分溶解
A20℃酒精10 mL50 g硝酸钾几乎不溶解
B20℃10 mL5 g食盐部分溶解
C80℃20 mL5 g硝酸钾全部溶解
D80℃10 mL10 g硝酸钾全部溶解

答案

答案:B

根据对照实验的设计方法,只能允许一个变量,也就是说选择与实验I只有一个变量,再分析结论.A、溶剂种类、加入固体质量都不同,所以A错;

B、只有加入的固体种类不同,所以B正确;

C、温度、溶剂体积都不同,故C错;

D、温度,加入的固体质量都不同,故D错.

故选B.

阅读理解

阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项,并在答题卡上将该项涂黑。

B

Most parents love the Internet and want their kids to use it. But a new survey in America finds almost as many also fear the online world—especially social networking sites such as My Space—and worry their kids will get in trouble with people they meet.

“The parents see the web’s incredible potential(可能性), and they know their kids have to be there.” says James Steyer, CEO of Common Sense Media, which released results from a survey that looked into parental attitudes toward the Internet. “It is also what they are scared of most.”

The study was conducted online May 5-10 by Insight Research Group. It says 80% of parents are concerned about kids meeting bad people online. That’s because young people who largely have grown up with the Net think of it as a social outlet(出口), say the researchers. To young people, the benefits of giving out some personal information to reach out to friends outweigh the risks. And the study shows they are so comfortable with the medium that 78% have a personal website or blog.

Parents also recognize the importance of the Internet. The survey shows 91% think the Net helps their children explore their passions, and 77% think the Internet is one of the most valuable education tools teens have. But 88% think it’s important to know what their kids are doing online.

Findings suggest both parents and teens need more education about using online media, Steyer says.

Internet safety has become an increasing concern for parents in America. Organizations like the Non-profit Common Sense have been trying to reach and help parents pay attention to the problem.

小题1: In the second paragraph, the underlined word “It” refers to_____.

A.Common Sense Media

B.the result of the survey

C.the web’s incredible potential

D.the website called My Space小题2:Why do young people give out their personal information?

A.They think it has more advantages than disadvantages.

B.They want to make themselves famous by doing that.

C.They want to have a personal website each.

D.They want to get some information from others.小题3: Most parents think it is important to know_____.

A.where their children give out the information

B.what kind of websites they have

C.how often they go online

D.what their children are doing online小题4:From the passage we can infer that_____.

A.children are too young to know how to use the Internet

B.parents must teach their children how to use the Internet

C.parents also need to learn more about using the Internet

D.the Internet is the most valuable tool for children to learn

填空题