单选题 Dr. Bergsten also has served on the senior staff of the National Security Council, 1969-71, and as a senior fellow of the Brookings Institution, another prominent Washington "think-tank'.
A. permanent B. famous
C. president D. important

【正确答案】 D
【答案解析】prominent“突出地、显著的”；permanent“永恒的”；famous“有名的”；important“重要的”。