Advice to "sleep on it" could be well founded, scientists say. After a good night's sleep a problem that couldn't be solved the night before can often appear more manageable. Researchers at the University of Luebek in Germany have designed an experiment that shows a good night's sleep can improve insight（顿悟）and problem-solving ability.
“If you have some newly-got memories in your brain, sleep acts on these memories and restructures them, so that after sleep the insight increases," said Dr Jan Born, a neuroscientist, at the University. To test the discovery, they taught volunteers two simple rules to help them turn a string of numbers into a new order. There was also a third, hidden rule, which could help them increase their speed in solving the problem. The researchers divided the volunteers into two groups: half were allowed to sleep after the training while the rest were forced to stay awake. Dr Jan Born and his team noticed that the group that had slept after the training were twice as likely to figure out the third rule as the other group. "Sleep helped," Born said in a telephone interview .¨The important thing is that you have to have a memory description of the problem you want to solve in your brain and then you sleep, so it can act on the problem."
But Born admitted that he and his team don't know how restructuring of memories occurs or what controls it. Pierre Maquet and Perrine Ruby of the University of Liege in Belgium said the experimental evidence supports the suggestion that sleep can help develop creative thinking. Although the role of sleep in human creativity will still be a mystery, the research gives people good reasons to fully respect their periods of sleep, they added.
What is the purpose of the experiment?

A．To test problem-solving ability in sleep.

B．To discover people's insight during sleep.

C．To prove a good sleep helps solve problems.

D．To discuss how to improve sleeping quality.

How did Jan Born and his team carry out the experiement ?

A．Through comparison.	B．Through interview.
C．Trough talking	D．Through imagination.

What can be inferred from Paragraph 2 ?

A．Sleep can help solve problems.

B．People should sleep as long as they want.

C．Different people have various periods of sleep.

D．Scientists know how sleep restructures memories from now.

Which of the following is TRUE about the experiments evidence?

A．It helps scientists control memories.

B．It explains the role of sleep in human.

C．It shows people's sleeping well helps a lot.

D．It shows how to develop creative thinking.