Do you sleep well? Some people get off to sleep as soon as the head hits the pillow, but many others are not so lucky．In fact，the lack of quality sleep has become a public health issue around the world．According to the World Association of Sleep Medicine，45 percent of the world’s population suffer from sleep problems．One in eight people don’t sleep well and are easily woken．7．6 percent sleep less than 3 hours each night．Some even can not fall asleep for several days in a row．
As a basic bodily and mental need，sleep is essential for our survival．It helps us to fight diseases，strengthen our memory, perform better in work and school and improve our quality of life．Lack of sleep is known to have a significant negative influence on health，both in the short and long term．Poor sleep has been associated with obesity, weakened immune systems and even some cancers，as well as depression and anxiety．
The World Sleep Day, held on the third Friday of March，is an annual celebration of sleep to lighten the burden of sleep problems through better prevention and management of sleep disorders．
Unhealthy lifestyle may be the first to blame for sleeplessness．More and more people use cellphones and computers in bed，with many staying up until midnight．Modern technology does make our life convenient，but abuse of it ruins our health．Environmental conditions，such as temperature，noise，light，bed comfort also play an important role in one’s ability to get proper sleep．Besides，improper evening diet，like a full or an empty stomach，coffee and alcohol all contribute to sleep problems．Of course，when it comes to causing poor sleep stress from finances，family or work should never be ignored．
However, those who suffer from sleep disorders don’t necessarily have to continue to do so—most sleep problems can be solved．
What can be inferred from Paragraph 1 ？

A．Nobody can stay awake for several days．

B．All people are going through sleep problems．

C．Sleep problems have become a worldwide concern．

D．The majority of the world’s population can’t sleep well．

What does Paragraph 4 mainly tell us?

A．The influences of lack of sleep．

B．The possible causes of poor sleep．

C．Poor sleep is associated with illness．

D．Good sleep helps us to perform better.

What will be discussed in the paragraph that follows?

A．The harm of sleep problems．

B．Activities on the World Sleep Day．

C．Interviews of poor sleep sufferers．

D．Measures against sleep problems．