概括句子大意和完成句子
More than 8 hours sleep too much of a good thing
1.Although the dangers of too little sleep are widely known，new research suggests that people who sleep too much may also suffer the consequences.
2.Investigators at the University of California in San Diego found that people who clock up 9 or 10 hours each weeknight appear to have more trouble falling and staying asleep，as well as a number of other sleep problems，than people who sleep 8 hours a night.People who slept only 7 hours each night also said they had more trouble falling asleep and feeling refreshed after a night’s sleep than 8-hour sleepers.
3.These findings, which Dr. Daniel Kripke reported in the journal Psychosomatic Medicine, demonstrate that people who want to get a good night’s rest may not need to set aside more than 8 hours a night.He added that“it might be a good idea'’for people who sleep more than 8 hours each night to consider reducing the amount of time they spend in bed, but cautioned that more research is needed to confirm this.
4.Previous studies have shown the potential dangers of chronic shortages of sleep一for instance, one report demonstrated that
people who habitually sleep less than 7 hours each night have a higher risk of dying within a fixed period than people who sleep more.
5.For the current report，Kripke reviewed the responses of 1，004 adults to sleep questionnaires，in which participants indicated how much they slept during the Week and whether they experienced any sleep problems.Sleep problems included waking in the middle of the night，arising early in the morning and being unable to fall back to sleep，and having fatigue interfere with day-to-day functioning.
6.Kripke found that people who slept between 9 and 10 hours each night were more likely to report experiencing each sleep problem than people who slept 8 hours.In an interview, Kripke noted that long sleepers may struggle to get rest at night simply because they spend too much time in bed.As evidence，he added that one way to help insomnia is to spend less time in bed.“It stands to reason that if a person spends too long a time in bed, then they’ll spend a higher percentage of time awake.”he said.
1. Paragraph 2 ___.
2. Paragraph 4___.
3. Paragraph 5___.
4. Paragraph 6___.
A. Keprike’s research tool
B. Dangers of Habitual shortages of sleep
C. Criticism on Kripke’s report
D. A way of overcoming insomnia
E. Sleep problems of long and short sleepers
F. Classification of sleep problems
5.To get a good night’s rest，people may not need to ___.
6.Long sleepers are reported to be more likely to___.
7.One of the sleep problems is waking in the middle of the night，unable to___.
8. One survey showed that people who habitually ___each night have a higher risk of dying.
A fall asleep again .
B become more energetic the following day
C sleep less than 7 hours
D confirm those serious consequences
E suffer sleep problems
F sleep more than 8 hours
Soot and snow: a hot combination
l New research from NASA scientists suggests emissions of black soot alter the way sunlight reflects off snow．According to a computer simulation，black soot may be responsible for 25
percent of observed global warming over the past century． 2 Soot in the higher latitudes of the Earth，where ice is more common，absorbs more of the sun’s energy and warmth than an icy, white background．Dark-colored black carbon，or soot，absorbs sunlight，while lighter colored ice reflects sunlight． 3 Soot in areas with snow and ice may play all important role in climate change．Also，if snow and ice covered areas begin melting。the warming effect increases，as the soot becomes more concentrated on the snow surface．“This provides a positive feedback，as glaciers and ice sheets melt,they tend to get even dirtier,” said Dr．James Hansen，a researcher at NASA’s Goddard Institute for Space Studies，NewYork．
4 Hansen found soot’s effect on snow albedo(solar energy reflected back to space)，which may be contributing to trends toward early springs in the Northern Hemisphere，such as thinning Arctic sea ice，melting glaciers and permafrost．Soot also is believed to play a role in changes in the atmosphere above the oceans and land．
5 “Black carbon reduces the amount of energy reflected by snow back into space，thus heating the snow surface more than if there were no black carbon~，”Hansen said．Soot’s increased absorption of solar energy is especially effective in warming the world’