问题 问答题 简答题

什么是有效余氯?它与人体健康有什么关系?

答案

参考答案:

自来水多以氯气消毒,当氯气溶于水中会变成次氯酸或次氯酸根离子,即俗称有效余氯。由于次氯酸具有极高的氧化能力,如自来水含有效余氯,它在配水管中停留时可预防细菌(病原菌)的滋生,因此有效余氯在自来水的安全卫生上扮演极重要的角色。为了卫生,自来水含有效余氯是必要的。

阅读理解

A famous study was done in a school by a professor (教授) from a university. At the start of the school year, the teachers were given the names of five children. They were told that these five were the most excellent students in the class. But the fact was that these students were only average(中等),and they were not the best students at all. Well, guess what? At the end of the year, all the five average students scored among the highest in the class.

  What made these average students change so much to become top students?The only difference was the change in their teachers’ attitude(态度). Because the teachers believed that these five kids were the top students,they expected(期望) more from them. And so these five average students began to believe and expect more from themselves. So they worked harder to do as well as they could.

  Do you know why? If you expect the best from people, they’ll usually want to give you their best. A great leader said, “Treat(对待) a person just how he appears to be on the outside, and you’ll make him even worse. But treat a person like he’s already a success,and you’ll help make him the best he can be.”

  Like the true story of 7-year-old Johnny, his teacher got so angry with him that one day she said,“Johnny,you’re the naughtiest(最顽皮的) boy in this class. I’m sure you’ll never change.” The next year Johnny had a new teacher. And on the first day of class,she met with Johnny after school and said,“Johnny, I’ve heard a lot about you! But do you know that I don’t believe a word of it.” And every day after that, this new teacher treated Johnny as if he was one of the smartest students even when Johnny did naughty things. Later on, Johnny became a school leader. Because that’s the power of our belief(信任) and attitude(态度) toward children.

小题1:The professor started his research(研究)by _______.

A.teaching the five children himself

B.asking the five children to find a new teacher

C.telling the five students to work harder than ever before

D.telling the teacher the five students were the best in the class小题2:The five average students became top students mainly because of ________.

A.the professor’s study

B.the teachers’ hard work

C.the change in the teachers’ attitude

D.the change in the professor’s attitude小题3:Why did the writer tell us the story of 7-year-old Johnny?

A.To let us know how good his new teacher was.

B.To show the importance of encouragement.

C.To show that the boy was clever enough.

D.To let us know the famous boy.小题4:The writer writes the passage mainly by ______.

A.giving reasons and result

B.giving result and examples

C.describing what he thinks

D.asking and answering questions小题5:What does the passage mainly tell us?

A.If you want to get more,you should have new teachers.

B.A professor’s study can help you score highest.

C.Only teachers can make you a top student.

D.Attitude and belief can change a person.

填空题