20．
A．restore
F．tempted | B．adjustment
G．addressed | C．sensitive
H．vary | D．unnatural
I．leave | E．quality
J．uninterrupted |
It is common to have difficulties sleeping during the day．Humans are born naturally to sleep best at night and be awake during the day．However，modern work schedules require some people to try to adapt the（41）D schedule of shift work （輪班）-being awake at night and sleeping during the day．
In order to make this（42）Bacceptable to you，you need to pay special attention to your sleep environment and your preparation for sleep．If shift work is a necessary part of your work life，here are some suggestions that may help．
Arrange to sleep in a（n）（43）Jcondition．This means you may have to unplug your phone，hang darkening curtains on the windows or wear a sleep eye mask，and ask your family and friends to （44）Iyou alone while you sleep．
Fit in a nap．When your daytime sleep period is too short，taking a short nap of less than 30minutes just before work or on a break has been shown to（45）A energy and enhance performance．
Develop and follow a sleep routine．It's best if you go to sleep and wake up at the same time every day．Try not to（46）Hthis too much on weekends．Your body likes routine．
Take extra care to make healthy choices．You may be（47）F to reach for unhealthy foods or nicotine （尼古�。� to stay awake or alcohol to try to sleep．But in the end these choices are more harmful than helpful．
If you have tried all these things and are still having problems getting enough（48）Esleep during the day，talk to your doctor or a sleep specialist．Sometimes medical treatment may be helpful and safe．In other cases，there may be a potential sleep disorder that needs to be（49）Gas soon as possible．
