问题 单项选择题

爆炸极限是表征可燃气体、蒸气和可燃粉尘爆炸危险性的主要示性数,其基本含义是指这类物质与空气的混合物在遇到火源后就会发生爆炸的( )范围。

A.温度
B.浓度
C.压力
D.点火能量

答案

参考答案:B

解析:当可燃性气体、蒸气或可燃粉尘与空气(或氧)在一定浓度范围内均匀混合,遇到火源发生爆炸的浓度范围称为爆炸浓度极限,简称爆炸极限。

阅读理解

When I was 13, my bedroom walls were covered with posters of the Monkees and Beatles. I wrote fan letters and daydreamed about meeting the objects of my affections. I begged my  parents to attend every rock concert and watch every TV show featuring my favorite celebrities; my friends and I discussed for hours all the things we would say and do when we met our favourite movie stars and pop singers. I drove my mother crazy ! But after a few years, my obsession stars faded as I matured and gained the confidence to socialize with “real” boys.

In the 35 years since I was a teenager, celebrity worship (崇拜) has increased among teens due to the explosion of television celebrity gossip shows, and instant access to celebrity news on the Internet. It’s no wonder that many teens are obsessed with stars when news programs are often filled with entertainment stories and the lives of celebrities.

Celebrity worship syndrome (综合征) is now considered a personality disorder. While it is normal for teenagers to follow the lives of their favorite stars, parents should try to monitor everything their child finds interesting. Parents should take action if they suspect a teen is too obsessed with celebrities and showing little interest in school or withdrawing from the family.  When teens talk a lot about celebrities and view them as just means of entertainment, this is considered normal celebrity worship. However, when a teenager is obsessed with a star and  often expresses a desire to have a close personal relationship with a celebrity or feels they have a special connection to a star, this may be the time for concern. Recent studies have shown that teens who develop an unhealthy obsession with celebrities often suffer from low self confidence and depression. Teens who are overly obsessed with stars often have damaged relationships with their parents.

小题1:The first paragraph is intended to tell us________.

A.parents needn’t worry about celebrity worship

B.celebrity worship can cause serious problems

C.it’s normal for a teen to have celebrity worship

D.celebrity worship only exists among teens小题2:We can learn from the second paragraph that________.

A.the media greatly contributes to celebrity worship today

B.the author is surprised at celebrity worship

C.teens today are not so obsessed with celebrities

D.celebrities expose their lives too much小题3:Parents should become concerned when their children________.

A.talk a lot about celebrities with others

B.put up celebrity posters in their bedrooms

C.ask to go to their favourite star’s concert

D.desire a close personal relationship with their favorite star小题4:The last paragraph implies that________.

A.parents should not care too much about a child’s celebrity worship

B.celebrity worship syndrome can be a serious problem if left overlooked

C.children can normally get out of celebrity worship when they are older

D.children with celebrity worship usually have high opinion of themselves小题5:What is most likely to be talked about in the paragraph following the passage?

A.The harm of celebrity worship syndrome.

B.More signs of celebrity worship syndrome.

C.What to do with children’s celebrity worship syndrome.

D.Who will suffer most from celebrity worship syndrome.

单项选择题