2017年6月英语四级（第3套 · 含听力）选词填空

Questions 26 to 35 are based on the following passage.
As if you needed another reason to hate the gym, it now turns out that exercise can exhaust not only your muscles, but also your eyes. Fear not, however, for coffee can stimulate them again. During __26__ exercise, our muscles tire as they run out of fuel and build up waste products. Muscle performance can also be affected by a __27__ called "central fatigue," in which an imbalance in the body's chemical messengers prevents the central nervous system from directing muscle movements __28__. It was not known, however, whether central fatigue might also affect motor systems not directly __29__ in the exercise itself, such as those that move the eyes. To find out, researchers gave 11 volunteer cyclists a carbohydrate (碳水化合物的) __30__ either with a moderate dose of caffeine (咖啡因), which is known to stimulate the central nervous system, or as a placebo (安慰剂) without, during 3 hours of __31__ . After exercising, the scientists tested the cyclists with eyetracking cameras to see how well their brains could still __32__ their visual system. The team found that exercise reduced the speed of rapid eye movements by about 8%, __33__ their ability to capture new visual information. The caffeine, the equivalent of two strong cups of coffee, was __34__ to reverse this effect, with some cyclists even displaying __35__ eye movement speeds. So it might be a good idea to get someone else to drive you home after that marathon.