A. while B. dark C. devised D. whereas E. specific F. agreeable G. regular H. stimulus I. disruption J. attain K. seek L. instructions M. spur N. formal O. available Most people who travel long distances complain of jetlag. Jetlag makes business travelers less productive and more prone to making mistakes. It is actually caused by 1 of your "body clock"—a small cluster of brain cells that controls the timing of biological functions. The body clock is designed for a 2 rhythm of daylight and darkness, so that it is thrown out of balance when it encounters daylight and darkness at the wrong times in a new time zone. The symptoms of jetlag often persist for days 3 the internal body clock slowly adjusts to the new time zone. Now a new anti-jetlag system is 4that is based on proven extensive pioneering scientific research. Dr. Martin Moore-Ede has 5 a practical strategy to adjust the body clock much sooner to the new time zone through controlled exposure to bright light. The time zone shift is easy to accomplish and eliminates most of the discomfort of jetlag. A successful time zone shift depends on knowing the exact time to either 6 or avoid bright light Exposure to light at the wrong time can actually make jetlag worse. The proper schedule for light exposure depends a great deal on 7 travel plans. Data on a specific flight itinerary and the individual's sleep pattern are used to produce a Trip Guide with 8 on exactly when to be exposed to bright light. When the Trip Guide calls for bright light you should spend time outdoors if possible. If it is 9 outside, or the weather is bad, or you are on an aeroplane, you can use a special light device to provide the necessary light 10 for a range of activities such as reading, watching TV or working.