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题库 / Prep2007E1-SC-82
Each year companies in the United States could save as much as $58 billion annually by preventing illness among employees and gain as much as $200 billion through improving performance of workers if they simply provided offices with cleaner air.
annually by preventing illness among employees and gain as much as $200 billion through improving performance of workers if they simply provided
annually if they prevented employee illness and gain as much as $200 billion through worker performance improved by simply providing
annually in employee illness prevention and gain as much as $200 billion through worker performance improved by simply providing
in employee illness prevention and gain as much as $200 billion through improving performance of workers if they simply provided
by preventing illness among employees and gain as much as $200 billion through improved worker performance if they simply provided
句意！
同问为啥improved. 另外by……和in都是状语，所以我用内涵和外延判断prevention应该是一个没有终点的的动作啊，所以是-ing
为什么through后面可以接improved?不是应该接improving吗？
annually与前面each year重复，排除ABC
improved worker performance，实质平行