I wasn't aware of this before, but recent research _____ that eating too much fat can contribute to heart disease. [ ]

A. has shown

B. will show

C. was showing

D. showed

德尔菲法的要点是（）

A.背靠背地征询意见

B.对专家意见进行统计归纳

C.要忠实于专家们的回答

D.沟通反馈意见

E.给专家们物质与精神奖励