[单项选择]How sleep helps us consolidate memories is still largely a mystery. A recent study from the University of Lǔbeck, in Germany, offers one clue. Subjects were given a list of 46 word pairs to memorize, just before sleep. Then when they reached the deepest stages of sleep, electrical currents were sent through electrodes on their heads to induce very slow brain waves. Such slow waves were induced at random in the brains of one group of subjects, but not another.
The next morning, the slow-wave group had better recall of the words. Other types of memory were not improved, and inducing the slow waves later in the night did not have the same effect. Why and how the slow waves improved memory is not yet understood, but they are thought to alter the strengths of chemical connections, or synapses, between specific pairs of nerve cells in the brain. Memories are "stored" in these synapses: changing the strength of the synapses increases the strength of the memories they store.
Slow wav
A. they were given a list of words before sleep.
B. they reached the deepest stages of sleep.
C. they were connected to electrical currents.
D. they were asked to recall the words the next mornin

[单项选择]
How sleep helps US consolidate memories is still largely a mystery. A recent study from the University of Liibeck, in Germany, offers one clue-Subjects were given a list of 46 word pairs to memorize, just before sleep. Then when they reached the deepest stages of sleep, electrical currents were sent through electrodes on their" heads to induce very slow brain waves. Such slow waves were induced at random in the brains of one group of subjects, but not another.
The next morning, the slow-wave group had better recall of the words. Other types of memory were no| improved, and inducing the slow waves later in the night did not have the same eftect. Why and how the slow waves improved memory is not yet understood, but they are thought to alter the strengths of chemical connections, or synapses, between specific pairs of nerve cells in the brain. Memories are "stored" in these synapses: changing the strength of th
A. Soon alter they fell asleep.
B. When they reached the deepest stage of sleep.
C. Just before they woke up.
D. At random time for each subject.

[单项选择]A. It helps to have a good sleep.
B. It helps to strengthen the bones.
C. It helps to supply enough blood to head.
D. It helps to exercise muscles in the body.

[单项选择]People who do sleep research tell us that a person is a sort of "information processor." We have two ways to use the information we get each day.
The first process is used when we are awake. It takes place in the left side of the brain. It is this process that makes us do the things we have to do. It lets us put aside those things that are not a real part of our day’s work.
The second process happens in the fight side of the brain. This process takes all those bits of information we did not use in the day. It turns them to dreams at night. "This process is our regular night shift work," says physiologist Rosalind Cartwright from the University of Illinois. "At night we put together the bits and pieces of our day, so that we are ready to face the next day."
We have several dreams each night of our lives. About ten minutes after we fall asleep, we begin to go through four stages of sleep. Our sleep gets deeper and deeper. And it gets harder for us to wake up. At the
A. people do odd things in the first stage of sleep
B. the left side of our brain is responsible for the work that is necessary to deal with during the day
C. the mysteries of dreams have just been brought to light
D. the function of the right side of our brain is to classify the information we fail to handle in the daytime

[填空题]Sleep is crucial for good health. It helps memory and (26) , keeps you fit, strengthens your immune system, fights inflammation and keeps your heart and blood (27) in tip-top shape.
While you’re snoozing, the body repairs damaged (28) , produces crucial hormones and strengthens memories—a process called consolidation, which helps you perform a new skill better after sleeping than you would if you spent an (29) amount of time awake. It’s a way for the body to (30) everything that happened over the past waking day and to kind of prepare for the next day.
Short sleepers, typically (31) people who get less than six hours of sleep at night, as well as people who don’t spend enough time in the deepest stages of sleep, are at higher risk of heart attacks and strokes than those who get at least seven hours.
It’s not clear why sleep may affect the heart, or if there is some (32) factor that affects y