[填空题]Everyone needs to sleep. If we don’t sleep enough, we often feel tired and irritable (烦躁的，易恕的). It seems there are two purposes of sleep: active sleep and passive sleep. The passive sleep gives our body the rest that is needed, and prepares us for active sleep, in which dreaming occurs. In passive sleep, the body is at rest. The heat slows down. The body processes become very slow. We move very little. And the brain becomes very inactive. If a person continues to sleep, she or he enters a new stage, a more active stage. The body goes through several changes: the brain temperature rises, the amount of blood in brain increases, the body becomes very still and the brain becomes active, the eyes begin to move rapidly, and the person is dreaming.
Throughout the night, people alternate between passive and active sleep. During eight hours of sleep, people dream for a total of one and a half hours on the average.
Many people say that they don’t dream, or that they rarely dream. D

[填空题]Everyone needs to sleep. If we don’t sleep enough, we often feel tired and irritable (烦躁的，易怒的). It seems there are two purposes of sleep: active sleep and passive sleep. The passive sleep gives our body the rest that is needed, and prepares us for active sleep, in which dreaming occurs. In passive sleep, the body is at rest. The heat slows down. The body processes become very slow. We move very little. And the brain becomes very inactive. If a person continues to sleep, she or he enters a new stage, a more active stage. The body goes through several changes: the brain temperature rises, the amount of blood in brain increases, the body becomes very still and the brain becomes active, the eyes begin to move rapidly, and the person is dreaming.
Throughout the night, people alternate between passive and active sleep. During eight hours of sleep, people dream for a total of one and a half hours on the average.
Many people say that they don’t dream, or that they rarely dream. Docto

[单项选择]

Everyone needs to sleep. If we don’t sleep enough, we often feel tired and irritable (易怒的).It seems there are two purposes of sleep: physical rest and emotional rest. We need to rest our bodies and our minds. Both are important in order for us to be healthy.
Each night we alternate (交替) between two kinds of sleep: active sleep and passive sleep. The passive sleep gives our body the rest that is needed, and prepares us for active sleep, in which dreaming occurs. In passive sleep, the body is at rest. The heart slows down. The body processes become very slow. We move very little. And the brain becomes very inactive. If a person continues to sleep, she or he enters a new stage, a more active stage. The body goes thro, gh several changes: the brain temperature rises, the amount of blood in brain increases, the body becomes very still and the brain becomes active. And as the brain becomes more active, the eyes begin to move rapidly, and the person is dreaming.
Th
A. to rest our bodies
B. to rest our arms and legs
C. to become less angry
D. both A and B

[单项选择]
What does the man mean [A] He needs sleep. [B] Kate shouldn’ t make such a big noise. [C] He is tired.

[单项选择]

All we have a clock located inside our brains. Similar to your bedside alarm clock, your internal clock runs on a 24-hour cycle. This cycle, called a circadian rhythm, helps control when you wake, when you eat and when you sleep.
Somewhere around puberty, something happens in the timing of the biological clock. The clock pushes forward, so adolescents and teenagers are unable to fall asleep as early as they used to. When your mother tells you it’s time for bed, your body may be pushing you to stay up for several hours more. And the light coming from your computer screen or TV could be pushing you to stay up even later.
This shift is natural for teenagers. But staying up very late and sleeping late can get your body’s clock out of sync with the cycle of light and dark. It can also make it hard to get out of bed in the morning and may bring other problems, too. Teenagers are put
A. it has a cycle of 24 hours
B. it controls when we wake, when we eat and when we sleep
C. it can alarm any time during 24 hours
D. it is a cycle also called circadian rhythm