维持意识的最重要的结构是（）

A.小脑

B.大脑灰质

C.大脑皮质

D.脑干上行性网状激活系统

E.脑干下行性网状激活系统

Questions 14-18

• A. professional and managerial employees
• B. work staff
• C. human-resource management
• D. work force skills
• E. important post
• F. the improvement of worker’s basic skills
• G. more money should be invested

The sustainable competitive advantage of American firms does not depend on ______.