听力材料：
Our brains are always working, even when we sleep.
Studies on sleep show that while we’re sleeping, our brains continue to work on problems that confused us during the day. We also know that sometimes the right answer to a problem might come to us more easily after eight hours of sleep.
Creativity and problem solving seem to be directly linked to getting enough sleep. In one study, two groups of college students were given a simple mathematics test. One group had just had eight hours of sleep, and the other group had seven hours of sleep or less. The students who had eight hours of sleep were three times more likely than the sleep-deprived students to figure out the correct answer in the math test.
The results of that study support research on the brain that indicates what happens to our memories during sleep. We think that our memories are reorganized and restructured during sleep before they are put into long-term storage in our brains. Our memories start in one area in the brain and are later pushed out to another part of the brain, where they can join up with other memories. This process, this transfer and restructuring of memories happens while we sleep. It seems to help our creativity in a way that makes it easier to solve a mathematical problem. The changes that improve our problemsolving ability happen during “slow wave” or deep sleep, which usually occurs in the first four hours of the sleep cycle.
This study has important results for students and workers who are overtired.It should remind us that sleep is often the best medicine. Too many people don't get enough sleep, and this contributes to accidents, health problems, and for students, lower test scores.
Question：
Using points and details from the talk, explain how sleep and problem solving are connected.
