— Do you think the article is difficult?    

— I think so. It took me a long time to _____ the new words in the dictionary. [ ]

A. look at

B. look out

C. look for

D. look up

投资方案经济评价中的基准收益率是指投资资金应当获得的（）盈利率水平。

A.最低

B.最高

C.平均

D.组合