People who work nightshifts are constantly fighting against

People who work nightshifts are constantly fighting against an internal clock in
People who work nightshifts are constantly fighting against an internal clock in their bodies.Quite often the clock tells them to sleep when their job requires them to remain fully awake.It’s no wonder that more accidents happen during night shifts than at any other time.Light therapy (光照疗法) with a bright light box can help night shift workers adjust their internal clock.However,many doctors recommend careful planning to help improve sleeping patterns.For example,night-shift workers often find it difficult to sleep in the morning when they get off work because the body’s natural rhythm(节律) fights back,no matter how tired they are.Some experts recommend that night-shift workers schedule two smaller sleep periods--- one in the morning after work,and another longer one in the afternoon,closer to when the body would naturally need to sleep.It’s also helpful to ask friends and family to cooperate by avoiding visits and phone calls during the times when you are sleeping.
\x051 Night-shift workers are those who __________.
\x05A have to rely on their internal clock B needs to re-adjust their clock
\x05C fall asleep late at night D have to work at night
\x05 2 In order to remain full awake at work,people working night-shifts should __________.
\x05A have longer sleep periods after work B make the light darker than usual
\x05C try to re-set their internal clock D pay more attention to their work
\x053 Many doctors think it is helpful to night-shift workers __________.
\x05A to sleep with a bright light on B to plan sleep patterns careful
\x05C to avoid being disturbed at work D to sleep for a long time after work
\x05 4 Night-shift workers often find it difficult to sleep in the morning because__________.
\x05A their internal clock will not allow them to B they are often disturbed by morning visits
\x05C they are not trying hard enough to do so D they are too tired to sleep well
\x055 According to the passage,some doctors recommend night-shift workers should __________
\x05A have frequent visits and phone calls B improve their family relationship
\x05C have two smaller sleep periods D remain mainly on light therapy

D,C,B,A,C