题目内容：
No Jetlag(时差反应)AnymoreMost people who travel long distances complain of jetlag(时差反应)． Jetlag makes business travelers less productive(多产的,有成效的)and more prone 1 making mistakes． It is actually caused by 2 of your "body clock"--a small cluster(串,组,群)of brain cells that controls the timing of biological 3 ． The body clock is designed for a regular rhythm(节奏)of daylight and darkness, so that it is thrown out of balance when it experiences daylight and darkness at the "wrong" times in a new time zone． The 4 of jetlag often persist(持续) for days 5 the internal body clock slowly adjusts to the new time zone．
Now a new anti-jetlag system is available that is based on proven 6 pioneering scientific research． Dr． Martin Moore has devised a practical strategy to adjust the body clock much sooner to the new time zone7 controlled exposure to bright light． The time zone shift(转)is easy to accomplish and eliminates(消除) 8 of the discomfort of jetlag．
A successful time z0ne shift depends on knowing the exact times to either 9 or avoid bright light． Exposure to light at the wrong time can actually make jetlag worse． The proper schedule10 light exposure depends a great deal on 11 travel plans．
Data on a specific flight itinerary(旅行路线)and the individual's sleep 12 are used to produce a Trip Guide with 13 on exactly when to be exposed to bright light．
When the Trip Guide calls14 bright light you should spend time outdoors if possible． If it is dark outside, or the weather is bad,15 you are on an aeroplane, you can use a special light device to provide the necessary light stimulus(刺激)for a range of activities such as reading, watching TV or working． A．for
B．from
C．to
D．of
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