7. Each year companies in the United State 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. A. annually by preventing illness among employees and gain as much as $200 billion through improving performance of workers if they simply provided B. annually if they prevented employee illness and gain as much as $200 billion through worker performance improved by simply providing C. annually in employee illness prevention and gain as much as $200 billion through worker performance improved by simply providing D. in employee illness prevention and gain as much as $200 billion through improving performance of workers if they simply provided E. by preventing illness among employees and gain as much as $200 billion through improved worker performance if they simply provided
答案选E。但大家觉得E中这两块对称吗 ? | 
