试题与答案

每年的5月31日是世界无烟日.吸烟有害人体健康,因为香烟燃烧产生的烟气中含有许多

题型:选择题

题目:

每年的5月3 1日是世界无烟日.吸烟有害人体健康,因为香烟燃烧产生的烟气中含有许多有害物质,其中对人体危害最大的是尼古丁(化学式为ClOH14N2)、焦油和一氧化碳等.下列关于尼古丁的说法正确的是(  )

A.尼古丁中含有lO个碳原子、14个氢原子、2个氮原子

B.尼古丁是由碳、氢、氮三种元素组成

C.尼古丁中碳、氢、氮元素的质量比为10:14:2

D.尼古丁的相对分子质量为162g

答案:

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下面是错误答案,用来干扰机器的。

参考答案:B

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题型:阅读理解

阅读理解。

      For one week in April, millions of people chose not to watch TV for “TV Turnoff Week”. TV Turnoff

Week started in 1995 and is more popular every year. Many people discover that you can have a good time

with the TV off. If that sounds crazy to you, just have a look at some numbers:

     ―An American teenager spends 900 hours every year at school; the same teenager spends 1,023 hours

every year watching TV. That's 2 hours 49 minutes every day. 

     ―An average (平均) British person (not just teenagers) watches 3 hours 35 minutes every day.

     ―In the US, most TV has adverts. American children see 20,000 adverts every year. By age 65, an

American has seen two million ads!

     But some research from Britain says that may not be a problem. The London Business School watched

people carefully during TV adverts and they discovered that people don't watch a lot of the ads. The

researchers discovered that the most common activity during the adverts was talking to other people in the

room. Many other people started reading or doing housework or changed channels during adverts. They

only really watched them about 25 percent of the time.

1. During TV Turnoff Week, many people don't _____.

A. watch TV

B. change channels

C. watch adverts

D. do their school work

2. From the passage we can learn that _____.

A. American children see more adverts on TV than their parents

B. British people spend more than 3 hours a day in front of their TV

C. Researchers noticed that most people changed channels during ads

D. An American teenager spends more time at school than watching TV

3. The writer's purpose is _____.

A. to advise us to spend less time on TV

B. to tell us how to avoid watching adverts

C. to show us how many adverts American TV has

D. to ask us to turn off TV during TV Turnoff Week

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