问题 选择题

下列说法正确的是(  )

A.放在碟里的酒精过一段时间后不见了是升华现象

B.冬天冰冻的衣服会变干是凝华现象

C.雾是水蒸汽液化形成的

D.霜的形成是凝固现象

答案

A、放在碟里的酒精过一段时间后不见了是由液态的酒精变成了气态,属于汽化现象.故A错误;

B、冬天冰冻的衣服会变干是由固态的冰直接变成了气态的水蒸气,属于升华现象.故B错误;

C、雾是由气态的水蒸汽液化形成的液态小水滴,属于液化现象.故C正确;

D、霜是由气态的水蒸气直接变成固态的小冰晶,属于凝华现象.故D错误.

故选C

阅读理解

You’re lost in the world of dreams and sleep. You roll over, smiling as you come across a swimming pool filled with chocolate. And then, your wonderful dream becomes a nightmare when someone is screaming, “Get up!” It’s just what every teenager goes through each morning!

Now, there seems to be one school that finally understands that requiring teens to show up at 9 am is not just cruel but also harmful to both the kids and the school.

The Monkseaton High School in North Tyneside, Britain, recently decided to experiment to see if there is any difference in student behavior if they just pushed back the start of their day by one hour, from 9 am to 10 am. And the results are surprising.

Since carrying out the later start, Monkseaton has seen a 28% drop in truancy, even hardly any lateness, and best of all, higher test scores. One of the reasons is that the teenagers are much happier to have the extra hour of sleep, but there is also a scientific reason behind why they need the extra sleep.

The school’s decision to push back the time was based on the research done by Oxford Professor Russell Foster, who pointed out that teenagers and adults have different sleep cycles, explaining why teenagers go to bed late and wake up late.

While adults are wide awake and ready at 8 am, teenagers are not fully awake until 10 am, sometimes even noon. Teachers may argue that their students perform better in the morning, but in fact, it is because they are in the zone while their students are still sleepy, making the students easier to control. Memory tests prove that the more difficult classes should be in the afternoon when teenagers are most wide awake.

The Monkseaton school officials are encouraged by the results and plan on voting to make it a permanent change.

小题1:What’s the best title of this passage?

A.Get up early, teenagers!

B.Finally, a school understands teenagers.

C.Why do teenagers stay up late?

D.Difference between teens and adults.小题2:What’s the meaning of the underlined word “truancy”?

A.grades

B.subject s

C.absence

D.classes小题3:What can we learn from the passage?

A.Teenagers and adults have the same sleep cycle.

B.Teenagers are fully awake at 10 am.

C.Teenagers are much happier to sleep than study.

D.Teenagers need the extra sleep also for a scientific reason.小题4:Which of the following statements is NOT true according to the passage?

A.The Monkseaton school is satisfied with the result of experiments.

B.It is cruel for the teenagers to show up at 9 am.

C.The Monkseaton school plans to change the school time forever.

D.Teenagers perform better in the morning than in the afternoon.

问答题 简答题