Some scientists declare ____ most of our fatigue comes from our mental and emotional (情感的) attitudes. One of England’s most outstanding _________ (scientist), J. A. Hadfield, says, “The ______ (great) part of the fatigue from which we suffer is of mental origin. In fact, fatigue of purely physical origin is rare.” Dr. Brill, a famous American scientist, goes even further. He declares, “One hundred percent of the fatigue of a sitting worker in good health is _______ emotional problems.” What kinds of emotions make sitting workers tired? Joy? Satisfaction? No! A feeling of being bored, anger, anxiety, tenseness, worry, a feeling of not being appreciated - those are the emotions that tire sitting workers. Hard work by _____ (it) seldom causes fatigue. We get tired ________ our emotions produce nervousness in the body.

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