School homework and use of electronic devices（电子仪器）are main causes， a report says． More than 60% of children and teens do not get adequatesleep， which can put their health at risk， according to a report that came out on Sunday by the Chinese Sleep Research Society． The report was from a survey at the end of last year and in January． It covered nearly 70，000 children and teens aged 6 to 17 across the Chinese mainland， Hong Kong， Macao and Taiwan．

The report found that the heavy school homework load（负荷）and the popularization of electronic devices were the two top causes for the inadequate sleep． From Monday to Thursday， 8． 4% of the group would still be busy with their homework after 11 p． m． More than 41% of children and teenagers who sleep too little use electronic devices， and children whose parents use smartphones in front of them are more probably to have less sleep． Other reasons， such as noise and light pollution， made the problem happen， the report said． The survey also showed that good sleep results in higher efficiency（效率）in study．

Gao Xuemei，vice﹣president of the society， said studies have shown that decreasing（减少）sleeping time for children and teenagers has been a global trend（全球趋势）in the past 10 years，but the problem appears to be worse in East Asia， including China， largely because of a heavier load of school homework．

"Lack（缺失）of sleep among children and teenagers is worth paying high attention to，because it can seriously affect their health and growth，" she said． "Such a group should sleep at least eight hours a day，" she added． "Sleep develops growth， protects the brain and improves the immune system（免疫系统），" she said． "Long﹣term lack of sleep will bring risks of diseases（疾病）and conditions such as dementia（痴呆）and cause lasting health harm．"

（1）The word "adequate" in Paragraph 1 probably means " 　　"．

A．	enough
B．	much
C．	necessary
D．	helpful

（2）The two top causes for the inadequate sleep are 　　．

A．	noise and the heavy school homework
B．	light pollution and the heavy school homework
C．	the heavy school homework and electronic devices
D．	Delectronic devices and noise

（3）From the passage we can learn 　　．

A．	the more children sleep，the higher their grades are
B．	parents influence their children less if they use smartphones
C．	noise and light pollution play an important role in the sleeping problem
D．	children in East Asia may lack more sleep than those in other parts of the world

（4）Sleep helps us a lot EXCEPT 　　．

A．	developing growth
B．	protecting the brain
C．	improving the immune system
D．	bringing risks of diseases

（5）The writer wants 　　by the passage．

A．	to find out the reasons for children's inadequate sleep
B．	to stop children and teenagers using electronic devices
C．	us to pay high attention to lack of sleep among children and teenagers
D．	us to cut down children and teenagers′ heavy school homework